Category Archives: Integrated Vector Management

Malaria News Today 2020-10-26: Haiti, India, Malaysia, Cape Verde

Recent news and abstracts explore malaria on three continents. Genetic aspects of malaria are studied in Haiti as well in Malaysia. Use of fish to control malaria carrying mosquitoes are successful in India. The movement toward malaria elimination is examined in Cape Verde. Finally, Non-invasive diagnostic tests are recognized/rewarded by NIH. Read more by following the links below.

NIH Awards Prize to Hemex Health’s Non-Invasive Sickle Cell, Malaria, Anemia Rapid Test (“SMART”) Diagnostic Technology

Researchers from Hemex Health, Medtronic plc, Case Western Reserve University, and the University of Nebraska Medical Center’s International Foundation Against Infectious Disease in Nigeria (IFAIN) were awarded 3rd place and $100,000 in the NIH Technology Accelerator Challenge.  Code named, SMART (Sickle, Malaria, Anemia, Rapid Test), the system includes non-invasive diagnostics for sickle cell, malaria, and anemia. The project seeks to build on Hemex Health’s Gazelle® platform, which currently includes minimally invasive tests (using a drop of blood) for malaria, the detection and quantification of hemoglobin variants, as well as for total hemoglobin for anemia determination.

The non-invasive test will screen for anemia, malaria, and sickle cell disease using an optical finger sensor similar to the way blood oxygen is measured. An advantage of combining the non-invasive and minimally invasive diagnostics is, when needed, more diagnostic information and confirmation is available on the same platform. The goal is a one-minute, $0.25 non-invasive malaria, sickle cell, and anemia test. “The world desperately needs easy-to-use diagnostic technologies with the flexibility needed to meet viruses and diseases in every corner of the planet,” said Ms. White.

Controlling Mosquitoes: Ramanathapuram district inches closer to malaria-free status

Steps taken by the Ramanathapuram district administration to control mosquito breeding for the last five years has enableed the district inch closer to being declared a ‘malaria-free district, with only one malarial fever case having been reported till September, this year. Last year, the district reported 43 cases.

One of the initiatives is to bring guppy fish from the Ayyankulam tank in Tiruvannamalai district and let them into all wells and tanks of the districts in 3:1 ratio (3 familes/one male). The fish thrives, eating the mosquito larvae and eggs and the incidence of malaria came down in the district.

Updates on malaria epidemiology and profile in Cabo Verde from 2010 to 2019: the goal of elimination

Located in West Africa, Cabo Verde is an archipelago consisting of nine inhabited islands. Malaria has been endemic since the settlement of the islands during the sixteenth century and is poised to achieve malaria elimination in January 2021. The aim of this research is to characterize the trends in malaria cases from 2010 to 2019 in Cabo Verde as the country transitions from endemic transmission to elimination and prevention of reintroduction phases. All confirmed malaria cases reported to the Ministry of Health between 2010 and 2019 were extracted from the passive malaria surveillance system.

A total of 814 incident malaria cases were reported in the country between 2010 and 2019, the majority of which were Plasmodium falciparum. Cabo Verde has made substantial gains in reducing malaria burden in the country over the past decade and are poised to achieve elimination in 2021. However, the high mobility between the islands and continental Africa, where malaria is still highly endemic, means there is a constant risk of malaria reintroduction. Characterization of imported cases provides useful insight for programme and enables better evidence-based decision-making to ensure malaria elimination can be sustained.

Genetic analysis reveals unique characteristics of Plasmodium falciparum parasite populations in Haiti

With increasing interest in eliminating malaria from the Caribbean region, Haiti is one of the two countries on the island of Hispaniola with continued malaria transmission. While the Haitian population remains at risk for malaria, there are a limited number of cases annually, making conventional epidemiological measures such as case incidence and prevalence of potentially limited value for fine-scale resolution of transmission patterns and trends. In this context, genetic signatures may be useful for the identification and characterization of the Plasmodium falciparum parasite population in order to identify foci of transmission, detect outbreaks, and track parasite movement to potentially inform malaria control and elimination strategies.

This study evaluated the genetic signals based on analysis of 21 single-nucleotide polymorphisms (SNPs) from 462 monogenomic (single-genome) P. falciparum DNA samples extracted from dried blood spots collected from malaria-positive patients reporting to health facilities in three southwestern Haitian departments (Nippes, Grand’Anse, and Sud) in 2016.

437 of the 462 samples shared high levels of genetic similarity–at least 20 of 21 SNPS–with at least one other sample in the dataset. These results revealed patterns of relatedness suggestive of the repeated recombination of a limited number of founding parasite types without significant outcrossing. These genetic signals offer clues to the underlying relatedness of parasite populations and may be useful for the identification of the foci of transmission and tracking of parasite movement in Haiti for malaria elimination.

Epidemiology of malaria among pregnant women during their first antenatal clinic visit in the middle belt of Ghana

A total of 1655 pregnant Ghanaian women aged 18 years and above with a gestational age of 13–22 weeks, who attended an antenatal care (ANC) clinic for the first time, were consented and enrolled into the study. A structured questionnaire was used to collect socio-demographic and obstetric data and information on use of malaria preventive measures. Venous blood (2 mL) was collected before sulfadoxine-pyrimethamine administration. Malaria parasitaemia and haemoglobin concentration were determined using microscopy and an automated haematology analyser, respectively.

One out of five pregnant women attending their first ANC clinic visit in an area of perennial malaria transmission in the middle belt of Ghana had Plasmodium falciparum infection. Age???25 years, multigravid, educated to high school level or above, and in household with higher socio-economic status were associated with a lower risk of malaria parasitaemia. Majority of the infections were below 1000 parasites/µL and with associated anaemia. There is a need to strengthen existing malaria prevention strategies to prevent unfavourable maternal and fetal birth outcomes in this population.

Genetic diversity of circumsporozoite protein in Plasmodium knowlesi isolates from Malaysian Borneo and Peninsular Malaysia

Understanding the genetic diversity of candidate genes for malaria vaccines such as circumsporozoite protein (csp) may enhance the development of vaccines for treating Plasmodium knowlesi. Hence, the aim of this study is to investigate the genetic diversity of non-repeat regions of csp in P. knowlesi from Malaysian Borneo and Peninsular Malaysia.
The phylogenetic analysis revealed indistinguishable clusters of P. knowlesi isolates across different geographic regions, including Malaysian Borneo and Peninsular Malaysia.

The csp non-repeat regions are relatively conserved and there is no distinct cluster of P. knowlesi isolates from Malaysian Borneo and Peninsular Malaysia. Distinctive variation data obtained in the C-terminal non-repeat region of csp could be beneficial for the design and development of vaccines to treat P. knowlesi.

Malaria News Today 2020-10-05: Concerns from Mali, Comoros, Ecuador, Southeast Asia and More

News and abstracts provide more on the surge of malaria in Mali. COVID-19 complicates malaria elimination in Southeast Asia. Peace Corps health care for volunteers in Comoros is questioned. Malaria risk in Ecuador is investigated. Risk maps are used/not used in three Sub-Saharan countries. The potential of microbiological control is considered. More information on each topic is available in the links provided.

Health workers raise alarm over surge in malaria cases, deaths in Mali

More details emerge on malaria in northern Mali. Medical workers in Mali raised an alarm over a surge in malaria cases which has seen at least 23 people killed by the disease in just the past one week. About 13,000 malaria cases were reported in the north by medical workers between September 21 and 27, representing an 88 percent increase in cases from the previous week. 59 people have died of malaria in the nation’s northern region since the beginning of the year, according to the ministry, which confirmed the deaths of the 23 people over the aforementioned September period.

Will COVID-19 hamper ASEAN’s fight to eliminate malaria?

Although progress elsewhere in the world has been slow, in the Asia-Pacific, deaths due to the mosquito-borne disease have dropped by 70% and cases have dropped by 22%. Within ASEAN, those figures—according to the Asia Pacific Leaders Malaria Alliance (APLMA)—are 92% and 67% respectively. The battle to eliminate malaria is continually evolving with different species of disease-carrying mosquitoes and parasites presenting new challenges. In 2008, a new strain of malaria that proved resistant to the anti-malarial drug artemisinin, nicknamed “super malaria”, emerged in Cambodia. It spread through the Greater Mekong region into Laos, Thailand and Vietnam and by 2017, it had developed resistance to another drug, piperaquine.

In response, scientists and researchers focused their resources on areas where the new strain was present and were making headway towards eliminating it. COVID-19 could threaten that progress. “We have enough evidence from the Ebola epidemic to suggest how progress on malaria elimination could be derailed and we are seeing some clear warnings now,” APLMA/APMEN commented. Historically, malaria cases have risen in countries where healthcare is interrupted due to conflict, disaster and war.

Peace Corps faces questions over death of volunteer from Inverness

By Sheryl Gay Stolberg of the New York Times reported that the Peace Corps, which suspended all operations for the first time in its history as the novel coronavirus raced around the globe, is facing renewed questions about the quality of its medical care — in particular, after the death of a 24-year-old volunteer from undiagnosed malaria — as it prepares to send volunteers back into the field.

An investigation by the Peace Corps inspector general documented a string of problems with Heiderman’s care. Her doctor had “limited training in tropical medicine,” the investigation found, and failed to test for malaria, which would have revealed that Heiderman had been infected by the deadliest malaria parasite. The Peace Corps was also using outdated 2006 guidelines for malaria, which did not reflect the current standard of care.

Anopheline and human drivers of malaria risk in northern coastal Ecuador

Understanding local anopheline vector species and their bionomic traits, as well as related human factors, can help combat gaps in protection. In San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sampled by both human landing collections (HLCs) and indoor-resting aspirations (IAs) and identified using both morphological and molecular methods.

Among 222 anopheline specimens captured, based on molecular analysis. The exophagic feeding of anopheline vectors in San Jose de Chamanga, when analysed in conjunction with human behaviour, indicates a clear gap in protection even with high LLIN coverage. The lack of indoor-resting anophelines suggests that indoor residual spraying (IRS) may have limited effect. The presence of asymptomatic infections implies the presence of a human reservoir that may maintain transmission.

How useful are malaria risk maps at the country level?

This study examined the perceptions of decision-makers in Kenya, Malawi and the Democratic Republic of Congo. Declining malaria prevalence and pressure on external funding have increased the need for efficiency in malaria control in sub-Saharan Africa (SSA). Modelled Plasmodium falciparum parasite rate (PfPR) maps are increasingly becoming available and provide information on the epidemiological situation of countries. However, how these maps are understood or used for national malaria planning is rarely explored. In this study, the practices and perceptions of national decision-makers on the utility of malaria risk maps, showing prevalence of parasitaemia or incidence of illness, was investigated.

Three different types of maps were used to show malaria epidemiological strata: malaria prevalence using a PfPR modelled map (Kenya); malaria incidence using routine health system data (Malawi); and malaria prevalence using data from the most recent Demographic and Health Survey (DRC). In Kenya the map was used to target preventative interventions, including long-lasting insecticide-treated nets (LLINs) and intermittent preventive treatment in pregnancy (IPTp), whilst in Malawi and DRC the maps were used to target in-door residual spraying (IRS) and LLINs distributions in schools. Maps were also used for operational planning, supply quantification, financial justification and advocacy. Findings from the interviews suggested that decision-makers lacked trust in the modelled PfPR maps when based on only a few empirical data points (Malawi and DRC). Despite the availability of national level modelled PfPR maps in all three countries, they were only used in one country.

Infection of highly insecticide-resistant malaria vector Anopheles coluzzii with entomopathogenic bacteria

This study found that Chromobacterium violaceum reduces its survival, blood feeding propensity and fecundity of mosquitoes in Burkina Faso. The study was motivated by the concern that malaria eradication will not be achieved without the introduction of novel control tools. Microbiological control might be able to make a greater contribution to vector control in the future. The interactions between bacteria and mosquito make mosquito microbiota really promising from a disease control perspective.
Methods

To assess entomopathogenic effects of C. violaceum infection on mosquitoes, three different types of bioassays were performed in laboratory. These bioassays aimed to evaluate the impact of C. violaceum infection on mosquito survival, blood feeding and fecundity, respectively. During bioassays mosquitoes were infected through the well-established system of cotton ball soaked with 6% glucose containing C. violaceum.

The data showed important properties of Burkina Faso C. violaceum strains, which are highly virulent against insecticide-resistant An. coluzzii, and reduce both mosquito blood feeding and fecundity propensities. However, additional studies as the sequencing of C. violaceum genome and the potential toxins secreted will provide useful information render it a potential candidate for the biological control strategies of malaria and other disease vectors.

 

Malaria News Today 2020-09-21: Vectors, Cities and Chimpanzees

First we look at how disease can influence urban planning. We have four news stories focus on field activities for vector control from Hyderabad, India, Borno State, Nigeria, Papua New Guinea and CHAD. Finally there is an ancestry article of sorts examining plasmodia in chimpanzees and humans. Click on the links to read full details.

Can Covid-19 inspire a new way of planning African cities?

Health crises are not new in Africa. The continent has grappled with infectious diseases on all levels, from local (such as malaria) to regional (Ebola) to global (Covid-19). The region has often carried a disproportionately high burden of global infectious outbreaks.
How cities are planned is critical for managing infectious diseases. Historically, many urban planning innovations emerged in response to health crises. The global cholera epidemic in the 1800s led to improved urban sanitation systems. Respiratory infections in overcrowded slums in Europe inspired modern housing regulations during the industrial era.

Urban planning in Africa during colonisation followed a similar pattern. In Anglophone Africa, cholera and bubonic plague outbreaks in Nairobi (Kenya) and Lagos (Nigeria) led to new urban planning strategies. These included slum clearance and urban infrastructure upgrades. Urban planning in French colonial Africa similarly focused on health and hygiene issues, but also safety and security.

Unfortunately regional experiences with cholera, malaria and even Ebola in African cities provide little evidence that they have triggered a new urban planning ethic that prioritises infectious outbreaks. Our recent research paper discusses three areas that can transform urban planning in the continent to prepare for future infectious outbreaks, using lessons from Covid-19.

The Coronavirus and other viruses like Ebola have always been ‘out there’ in nature.

But it’s only when we disrupt the natural habitats of the wild animals. Deadly viruses stay beneath the surface and need just one moment of triggering to emerge in the atmosphere and take the world by storm – historian Dr Mark Honigsbaum. The point is we cannot prevent all spillover events or predict precisely when or where the next one will happen. What we can do — and should do often — is invest in local laboratories and diagnostic services so that we can spot unusual outbreaks early and close them down quickly

We should note that Plasmidium Knowlesi is an example of a form of malaria from monkeys that arose because of urban expansion on forest habitats.

Hyderabad: People sensitised on mosquito breeding

As part of a novel initiative, every Sunday 10 am, 10 minute programme, the entomology wing of Greater Hyderabad Municipal Corporation conducted awareness drive on mosquito breeding grounds at various places on Sunday. They explained the importance of cleanliness and the ways the mosquito breeding takes place in stagnated water. Speaking on the occasion, Banjara Hills Corporator Gadwal Vijayalaxmi called upon everyone not to allow accumulation of water in containers, utensils and surroundings.

Borno, WHO Administer Malaria Prevention Drug on 2.1m Children

WHO National Coordinator Malaria Emergencies in Nigeria, Dr. Iniabasi Nglas gave the figure during a four round Malaria Chemoprevention Campaigns (MPCs aka SMC) in 25 of the 27 local government areas of Borno State. During the advocacy, Nglas said the IDP camps “are given special attention for there is high threat of malaria infection due to the environment. Record has shown that the treatment has reduced malaria morbidity in the state.” She revealed that during the first cycle, 1.9 million children were targeted but due to high reception 2.1 million children were administered with the drug.

Rotary Against Malaria Distributes Nets in PNG

ROTARY Against Malaria has finally completed its distribution of bed net mosquito nets throughout the Eastern Highlands Province (EHP) after three months. Team leader of Rotary Against Malaria in the province, Helmut Magino, during a ceremony in Goroka, acknowledged his working staff, the Eastern Highlands Provincial Health Authority, district health officers, logistic company Mapai Transport, Summer Institute of Linguistics (SIL)
and the communities in Papua New Guinea.

“Without these partners, our work in distributing mosquito nets wouldn’t have been successful,” Mr Magino said. “Mapai Transport assisted with vehicles to travel to the remote parts in Okapa, Henganofi and Lufa. “SIL assisted with distribution via airplane to remote parts which are not connected by road like in Obura-Wonenara district.” The volunteer-run organisation funded by Global Fund, a US-based organisation, distributed 145,900 mosquito nets in the province. “We distributed around 45,000 nets to Okapa and Lufa, 35,000 to Obura-Wonenara and 66,900 to rural areas in Goroka district. “We will visit EHP again next year to distribute nets …”

Donating Emergency IRS Supplies to CHAD

Last week, despite the COVID-19 pandemic, a Hercules military transport aircraft took off from an Israeli military base in the south, filled to capacity with items donated by Israeli Flying Aid IFA and the American Jewish Committee (AJC) — 2,000 six-person tents, personal protection equipment (PPE) for medical teams, backpack sprayers to eradicate malaria-carrying mosquitos, and more.

Why humans can run marathons and apes cannot (implication for plasmodium species)

Chimpanzees share more than 99 percent of their genes with modern humans, but the CMAH gene is one of the areas of difference. Two to three million years ago, gorillas, chimpanzees, and other primates were dying from a type of malaria called Plasmodium reichenowi (Science, 2011;331:540-542). At that time, all primates had a surface protein called Neu5Gc on their cells that was made from Neu5Ac. Then along came a primate with a gene that had lost its ability to make Neu5Gc from Neu5Ac, so it had only Neu5Ac (Proc Natl Acad Sci USA, Sept 6, 2005;102(36):12819-12824).

That pre-human did not die from malaria like other primates, his and her children lived and proliferated, and today their descendants (all humans) have a gene that makes Neu5Ac instead of Neu5Gc. As often happens in nature, the malaria parasite then modified its genetic makeup into a variant called Plasmodium falciparum which can infect humans, but not chimpanzees, so today humans can be infected only with Plasmodium falciparum and chimpanzees can be infected only with Plasmodium reichenowi. This same genetic mutation gave homo sapiens greater endurance so they were able to run long distances while the apes could not, which gave humans an advantage in hunting for food (J Hum Evol, 2014;66:64-82).

Malaria News Today 2020-09-20: Controlling Mosquitoes

Abstracts and news look at mosquito control measures including screening eaves and indoor residual spraying from Malaria Journal. Mosquito-associated bacteria, fungi, and even viruses represent untapped tools. Finally one can buy and wear a face mask and help eliminate malaria. Click the links to get more information

Evaluating effectiveness of screening house eaves

a potential intervention for reducing indoor vector densities and malaria prevalence in Nyabondo, western Kenya. Mosquito-proofing of houses using wire mesh screens is gaining greater recognition as a practical intervention for reducing exposure to malaria transmitting mosquitoes. Screening potentially protects all persons sleeping inside the house against transmission of mosquito-borne diseases indoors. The study assessed the effectiveness of house eaves screening in reducing indoor vector densities and malaria prevalence in Nyabondo, western Kenya. 160 houses were selected for the study, with half of them randomly chosen for eaves screening with fibre-glass coated wire mesh (experimental group) and the other half left without screening (control group).

At all the three parasitological follow-up survey points, house screening significantly reduced the malaria prevalence by 100% (p?<?0.001), 63.6% (p?=?0.026), and 100% (p?<?0.001) in the 1st, 2nd and 3rd follow-up surveys respectively. The study demonstrated that house eave screening has potential to reduce indoor vector densities and malaria prevalence in high transmission areas.

Rapid reduction of malaria transmission following the introduction of indoor residual spraying

in previously unsprayed districts: an observational analysis of Mopti Region, Mali, in 2017. The National Malaria Control Programme (NMCP) of Mali has had recent success decreasing malaria transmission using 3rd generation indoor residual spraying (IRS) products in areas with pyrethroid resistance, primarily in Ségou and Koulikoro Regions. In 2015, national survey data showed that Mopti Region had the highest under 5-year-old (u5) malaria prevalence at 54%—nearly twice the national average—despite having high access to long-lasting insecticidal nets (LLINs) and seasonal malaria chemoprevention (SMC). Accordingly, in 2016 the NMCP and other stakeholders shifted IRS activities from Ségou to Mopti. A set of retrospective, eco-observational time-series analyses were performed using monthly incidence rates of rapid diagnostic test (RDT)-confirmed malaria cases reported in the District Health Information System 2 (DHIS2) from January 2016 until February 2018.

At HFs in communities of Mopti where IRS was introduced in 2017, peak incidence fell by an average of 42% (CI95 31–63%) between these years, a significantly greater decrease (p?=?0.040) almost double what was seen in the comparator HFCAs. The opposite effect was observed in Ségou Region, where peak incidence at those HFs where IRS was withdrawn after the 2016 campaign increased by an average of 106% (CI95 63–150%) from year to year, also a significant difference-in-differences compared to the comparator no-IRS HFs (p?<?0.0001).

Annual IRS campaigns continue to make dramatic contributions to the seasonal reduction of malaria transmission in communities across central Mali, where IRS campaigns were timed in advance of peak seasonal transmission and utilized a micro-encapsulated product with an active ingredient that was of a different class than the one found on the LLINs used throughout the region and to which local malaria vectors were shown to be susceptible. Strategies to help mitigate the resurgence of malaria cases that can be expected should be prioritized whenever the suspension of IRS activities in a particular region is considered.

COVID-19 Mask Raises Money for Malaria Elimination

Goodbye Malaria was founded by African entrepreneurs who truly believe African creativity is the key to solving Africa’s biggest problems. “From saving lives to saving livelihoods – the birth of the Goodbye Malaria mask.”  Mask initiative helps to raise funds support on-the-ground malaria elimination in Southern Africa. it empowers local crafters to create stylish merchandise using Goodbye Malaria’s iconic shwe shwe fabric. Goodbye Malaria co-founder Kim Lazarus said: “We have never asked the public for donations, instead, offering consumers an opportunity to support malaria elimination efforts through their purchase of our merchandise.” (see photo above)

Prospects and Pitfalls: Next-Generation Tools to Control Mosquito-Transmitted Disease

Annual Review of Microbiology reports that Mosquito-transmitted diseases, including malaria and dengue, are a major threat to human health around the globe, affecting millions each year. A diverse array of next-generation tools has been designed to eliminate mosquito populations or to replace them with mosquitoes that are less capable of transmitting key pathogens. Many of these new approaches have been built on recent advances in CRISPR/Cas9-based genome editing. These initiatives have driven the development of pathogen-resistant lines, new genetics-based sexing methods, and new methods of driving desirable genetic traits into mosquito populations.

Many other emerging tools involve microorganisms, including two strategies involving Wolbachia that are achieving great success in the field. At the same time, other mosquito-associated bacteria, fungi, and even viruses represent untapped sources of new mosquitocidal or antipathogen compounds. Although there are still hurdles to be overcome, the prospect that such approaches will reduce the impact of these diseases is highly encouraging.

Tropical Health Update 2019-08-04: Ebola, Malaria Vectors, Snakebite and Trachoma

In the past week urban transmission in Goma, a city of at least 2 million inhabitants in eastern Democratic republic of Congo, was documented as a gold miner came home and infected his wife and child. To get a grip on the spread of the disease, DRC is considering another vaccine, not without some controversy. WHO provides detailed guidance on all aspects of response. On the malaria front we have learned more about malaria vectors, natural immunity and reactive case detection.

Ebola Challenges: Vaccines, Urban Transmission

The current Ebola vaccine being deployed to over 150,000 people in North Kivu and Ituri Provinces was itself an experimental intervention during 2016 when it was first used in the largest ever outbreak located in West Africa. BBC reports that, “World Health Organization (WHO) data show the Merck vaccine has a 97.5% efficacy rate for those who are immunised, compared to those who are not.”

The proposed addition of a Johnson and Johnson vaccine would be in that same experimental phase if introduced in DRC now. It has been proven safe as well as effective in other primates. The challenge is that even though the Merck vaccine supplies are near 500,000, this is not enough to cover the potential needs in an area with over 10 million people, although Merck is still producing more. At present, BBC says, “Those pushing for the use of the new Johnson & Johnson vaccine, had proposed using it to create a protective wall, vaccinating people outside the outbreak zone.” In addition, the new national response team is concerned that “Only about 50% of cases of Ebola in the Democratic Republic of Congo are being identified.”

Finally, there is the issue of community mistrust of government workers and challenging logistics. “There are also concerns that the new vaccine – which requires two injections 56 days apart – may be difficult to administer in a region where the population is highly mobile, and insecurity is rife.”

If efforts at vaccination are needed soon in Goma, up to 2 million doses might be needed. Reuters reports that, “Congolese authorities were racing to contain an Ebola epidemic on Thursday, after a gold miner with a large family contaminated several people in the east’s main city of Goma before dying of the hemorrhagic fever.” Readers may recall that the West Africa outbreak of 2014-16 in Guinea, Sierra Leone and Liberia accelerated greatly after infected people went to major cities in search of help.

The miner is the second ‘imported case into Goma, which borders Rwanda, but because his family lives there, he has already infected his wife and one of his 10 children. Contacts are being traced and monitored, but this urban and border threat is one of the factors that led WHO to finally declare the current outbreak a public health emergency.

Malaria

As we move toward malaria elimination Reactive Case Detection (RCD) has been proposed as an integral part of these efforts with the hopes that is can be conceived of as a way of gradually decreasing transmission, according to an article in Malaria Journal. In fact, the value of RCD may be limited as follows:

  • RCD alone can eliminate malaria in only a very limited range of settings, where transmission potential is very low
  • In other settings, it is likely to reduce disease burden and help maintain the disease-free state in the face of imported infections

Another article looks at “natural exposure to gametocytes that can result in the development of immunity against the gametocyte by the host as well as genetic diversity in the gametocyte.” The researchers learned that there can be variations in immune response depending on season and geography. This information is helpful in planning malaria elimination interventions.

On the vector front a baseline susceptibility testing was conducted in 16 countries in sub-Saharan Africa for neonicotinoids. “The target site of neonicotinoids represents a novel mode of action for vector control, meaning that cross-resistance through existing mechanisms is less likely.” The findings will help in the preparation for rollout of clothianidin formulations as part of national IRS rotation strategies by PMI and other partners.

Researchers also called on us to learn more about malaria vectors in other parts of the world. In order to eliminate Plasmodium falciparum from the Caribbean and Central America program planners should consider local vector characteristics such as An. albimanus. They found that, “House-screening and repellent IRS are potentially highly effective against An. albimanus if people are indoors during the evening.”

Vectors are also of concern on the edges of malaria transmission, particularly in South Africa, one of the ‘elimination eight’ countries of the Southern Africa Development Community. Researchers examined the, “potential role of Anopheles parensis and other Anopheles species in residual malaria transmission, using sentinel surveillance sites in the uMkhanyakude District of northern KwaZulu-Natal Province.” They found Anopheles parensis is a potential but minimal vector of malaria in South Africa “owing to its strong zoophilic tendency.” On the other hand, An. arabiensis was found to be the major vector responsible for residual malaria transmission in South Africa. Since these mosquitoes were found in outdoor-placed resting traps, interventions are needed to control outdoor-resting of vector populations.

NTDs of Concern

During the week, the member states of the African Union renewed their commitment to fight and permanently eliminate Neglected Tropical Diseases. Africa.com reported that, “Achievements to date include 1 billion people treated against at least one NTD and 37 countries have completed the removal of at least one NTD.”

Although some reports have discounted the idea of trachoma in Namibia, there may be reason to re-examine the situation. On Twitter Anthony Solomon notes that Namibia needs #trachoma prevalence surveys. A just-completed joint Ministry of Health & Social Services/@WHO mission found active trachoma & trichiasis in Zambezi & Kunene Regions.

The Times of India draws attention to snakebite. It says that “Under-reported and inadequately treated, fatalities in India are estimated at close to 50,000 a year, the world’s highest.”

Overall we can see that the concept of ‘neglect’ has several uses. There is neglect if half of Ebola cases are undetected. There is neglect if we do not understand malaria vectors in low transmission areas. Finally, there is neglect if we do not conduct up-to-date disease surveys to determine whether a disease is present or not. Elimination of tropical diseases is challenging when key processes are neglected.

The Weekly Tropical Health News 2019-07-13

In the past week more attention was drawn to the apparently never-ending year-long Ebola outbreak in the northeast of the Democratic Republic of the Congo. Regarding other diseases, there is new information on the RTS,S malaria vaccine, river prawns have been found to play a biological control role in schistosomiasis, and an update from the World Health Organization on essential medicines and diagnostics. New malaria vector control technologies are discussed.

Second Largest Ebola Outbreak One Year On

Ronald A. Klain and Daniel Lucey in the Washington Post observed raised concern that, “the disease has since crossed one border (into Uganda) and continues to spread. In the absence of a trajectory toward extinguishing the outbreak, the opposite path — severe escalation — remains possible. The risk of the disease moving into nearby Goma, Congo — a city of 1 million residents with an international airport.”

They added their voices to a growing number of experts who are watching this second biggest Ebola outbreak in history and note that, “As the case count approaches 2,500 with no end in sight, it is time for the WHO to declare the outbreak a public health emergency of international concern — a ‘PHEIC’ — to raise the level of global alarm and signal to nations, particularly the United States, that they must ramp up their response.” They call for three actions: 1) improved security for health workers in the region, 2) stepped up community engagement and 3) extended health care beyond Ebola treatment. The inability to adequately respond to malaria, diarrheal diseases and maternal health not only threated life directly, but also threated community trust, putting health workers’ lives at risk.

Olivia Acland, a freelance journalist based in DRC, reporting for the New Humanitarian describes the insecurity and the recent “wave of militia attacks in the Democratic Republic of Congo’s northeastern Ituri province has left hundreds dead and roughly 300,000 displaced in recent weeks, triggering a new humanitarian crisis in a region.” Specifically, “Ituri, a fertile region rich in gold deposits, has been an epicentre of conflict in Congo for decades. Between 1999 and 2003, around 60,000 people were killed here, as a power struggle between rebel groups escalated into ethnic violence,” related to traditional tensions between Hema cattle herders and Lendu farmers with roots in Belgian colonization.

Updates from the DRC Ministry of Health report on average 11 new Ebola cases per day in the past week. So far over 160,000 people have been vaccinated, and yet the spread continues. The Ministry also describes new protocol contains three vaccinations strategies that can be used depending on the environment in which confirmed cases are found including:

  • Classic Ring: The classic strategy of vaccinating contacts of confirmed cases and contact contacts.
  • Enlarged ring: It is also possible to vaccinate all inhabitants of houses within 5 meters around the outbreak of a confirmed case.
  • Geographical Ring: In an area where team safety can not be guaranteed, they can vaccinate an entire village or neighborhood.

Malaria Vaccines, Essential Drugs and New Vector Control Technologies

Halidou Tinto and colleagues enrolled two age groups of children in a 3-year extension of the RTS,S/AS01 vaccine efficacy trial: 1739 older children (aged 5–7 years) and 1345 younger children (aged 3–5 years). During extension, they reported 66 severe malaria cases. Overall they found that, “severe malaria incidence was low in all groups, with no evidence of rebound in RTS,S/AS01 recipients, despite an increased incidence of clinical malaria in older children who received RTS,S/AS01 compared with the comparator group in Nanoro. No safety signal was identified,” as seen in The Lancet.

WHO has updated the global guidance on medicines and diagnostic tests to address health challenges, prioritize highly effective therapeutics, and improve affordable access. Section 6.5.3 presents antimalarial medicines including curative treatment (14 medicines) for both vivax and falciparum and including tablets and injectables. Prophylaxis includes 6 medicines including those for IPTp and SMC. The latest guidance can be downloaded at WHO.

Paul Krezanoski reports on a new technology to monitor bednet use and tried it out in Ugandan households. As a result. “Remote bednet use monitors can provide novel insights into how bednets are used in practice, helping identify both households at risk of malaria due to poor adherence and also potentially novel targets for improving malaria prevention.

In another novel technological approach to vector control, Humphrey Mazigo and co-researchers tested malaria mosquito control in rice paddy farms using biolarvicide mixed with fertilizer in Tanzanian semi-field experiments. The intervention sections (with biolarvicide) had lowest mean mosquito larvae abundance compared to control block and did not affect the rice production/harvest.

Prawns to the Rescue in Senegal Fighting Schistosomiasis and Poverty

Anne Gulland reported how Christopher M. Hoover et al. discovered how prawns could be the key to fighting poverty and schistosomiasis, a debilitating tropical disease. They found that farming the African river prawn could fight the disease and improve the lives of local people, because the African river prawn is a ‘voracious’ predator of the freshwater snail, which is a carrier of schistosomiasis.

The researchers in Senegal said that, “market analysis in Senegal had shown there was significant interest among restaurant owners and farmers in introducing prawns to the diet.” The prawn could also for the basis of aquaculture in rice paddies and remove the threat of schistosomiasis from the rice workers.

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Agriculture and Promotion of Food Security Can Affect Malaria Transmission

The link between malaria and food security in a global context has been made. The influence of malaria on food security was examined. Now the connection between agriculture practices/food security and malaria is pursued below.

A common complaint with programs that distribute insecticide-treated bednets to prevent malaria is that the nets may be used for other purposes that the intended effort to prevent infected mosquitoes from biting people. All informants interviewed for a study in Western Zambia reported that ITNs are regularly used for fishing and the misuse is widespread. Unsustainable fishing practices, drought and population pressure were mentioned as reasons for fishery decline. The implication was that the use of free ITNs for fishing at least saved the population money in a time of declining fortunes.

A broader review of the ITNs for fishing issue was done through contacting expert witnesses across Africa. Mosquito net fishing (MNF) was found to be a broadly pan-tropical activity, particularly prevalent in sub-Saharan Africa. The authors found that, “Perceived drivers of MNF were closely related to poverty, revealing potentially complex and arguably detrimental livelihood and food security implications.”

The mosquito breeding potential of dams cuts across Africa with the number of dams located in malarious areas projected to increase according to Kibret and colleagues. This is because “The population at risk of malaria around existing dams and associated reservoirs, is estimated to increase from 15 million in 2010 to 21-23 million in the 2020s, 25-26 million in the 2050s and 28-29 million in the 2080s.” In addition, areas with dams but without malaria transmission at present, will likely transition to regions of unstable transmission due to climate change.

Likewise, a study in Ethiopia starts with the assertion that, “Dams are important to ensure food security and promote economic development in sub-Saharan Africa,” and then stresses the importance of understanding the consequences of these projects. The researchers found that “the mean monthly malaria incidence and anopheline larval density was generally higher in the dam villages than in the non-dam villages” in all the three dam settings studied. So while dams can increase agricultural production, the authors concluded that, “the presence of dams intensifies malaria transmission in lowland and midland ecological settings.”

Hydro-agricultural projects include dams and irrigation. Human bait mosquito captures volunteers in hydro-agricultural and river bank sites in Cameroon Akono et al. found that mosquito biting rates were higher in hydro-agricultural sites of less urbanized and urban settings than in natural river banks sites. An additional implication is that urban farming, an important component of food security, may influence mosquito and malaria prevalence.

Stoler and colleagues pursued this question of urban agriculture. The odds of self-reported malaria are significantly higher for women in Accra, Ghana who are living within 1 km of urban agriculture compared with all women living near an irrigation source, the association disappearing beyond this critical distance. Likewise in Kumasi, Afrane et al. learned that “adult and larval mosquito abundance and larval survival were high in the irrigated fields in the irrigated (urban) vegetable farm. This therefore, contributed significantly to adult mosquito populations and hence malaria transmission in the city.”

Even agricultural practices in smaller subsistence farms can foster malaria mosquito breeding. Practices found in southwest Nigeria include collection of pools of water in the farms for soaking cassava tubers, digging of trenches, irrigation of farms, and the presence of fish ponds.

Communities can perceive how agricultural practices may contribute to malaria. In Tanzania a fair number of rural respondents associated growing of rice with malaria. They also noted that the need to sleep on their farms at times meant they could not benefit from the mosquito nets hanging back in their house, some hours walk away. The idea of rice cultivation and malaria was tested in central Kenya. Mwangangi and co-researchers found that, “Rice fields and associated canals were the most productive habitat types,” for malaria mosquito breeding. Overall, Mboera et al. found, “evidence that malaria transmission risk varies even between neighbouring villages and is influenced by agro-ecosystems.”

Although we can establish the two-way link or intersection between malaria and food security, we can see that recommended joint or integrated programming may not always be optimal at various levels from the nation to the community. Greater collaboration between health and agricultural ministries and agencies is needed, supported by national policies that see malaria and food production as part of overall national development goals.

Malaria, Lymphatic Filariasis and Insecticide-treated Nets

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Throughout Africa one of the main vectors that carry Lymphatic Filariasis (LF) is the Anopheles mosquito, which also carries the malaria parasite. The Carter Center has been promoting use of insecticide treated nets (ITNs) for many years as part of its LF control efforts, but others may not have gotten the message.

The global community is targeting LF for elimination in 2020. The primary strategy is mass drug administration annually with ivermectin and albendazole. The plan is that up to seven annual rounds of drug distribution in endemic communities where 90% of population coverage is achieved is necessary to stop LF transmission. The Carter Center explains that distribution of long-lasting insecticidal bed nets (LLINs) protects pregnant women and children who cannot take drug treatment.

The LF strategy often builds on and integrates with onchocerciasis control efforts where these diseases overlap. The community directed treatment with ivermectin (CDTI) model pioneered by the African Program for Onchocerciasis Control  (APOC), wherein communities or villages plan together the distribution process including selecting their own community directed distributors (CDDs). This model has also been used to distribute ITNs.

20160818_100110-1A second component of the LF strategy is morbidity management which focuses on enhanced personal hygiene or cleaning of the parts of the body that experience lymphedema. Another aspect uses surgery to address some of the worst effects, hydrocele.  While this component does not ‘control’ LF, it is a necessary effort to reduce suffering and the negative stigma from the disease.

To judge whether transmission has stopped and elimination has been achieved Transmission Assessment Surveys (TAS) are conducted with rapid diagnostic tests on young children after at least 5 years of MDA in a community.  Specifically WHO recommends an implementation unit must have completed five effective rounds of annual MDA defined as achieving rates of drug coverage exceeding 65% in the total population.

For example the Carter Center in Support of the Nigerian Federal Ministry of Health worked in Plateau and Nasarawa States through community health education, delivery of long lasting insecticide-treated nets (LLINs) and 33 million drug treatments for lymphatic filariasis and river blindness between 2000 and 2011. “In 2012, it was confirmed (through TAS) that lymphatic filariasis transmission had stopped. Post-treatment surveillance is currently underway to assure that the parasite is not reintroduced into the area.”

Another component of the assessment process is yet to be fully realized. That is the testing of mosquitoes for the presence of microfilariae. This indirectly implies an important role in preventing human-vector contact as would be achieved through the use of ITNs as well as indoor residual spray (IRS).

Vector control can benefit more than one disease. Integrated vector management is seen as a key tool to prevent reintroduction of LF in areas where anopheles mosquitoes carry the disease and where ITN campaigns are successful.

Ultimately the key to benefiting from the disease control synergies provided by insecticide-treated nets is an understanding what if any effect nets have on transmission. This poses a challenge in terms of separating it from the effect of MDAs as well as the fact that MDAs are time-limited. As MDAs are still underway in many places it is incumbent on program managers to monitor and evaluate the impact of all activities, treatment and vector control, over the next decade to determine the success of eliminating LF and hopefully malaria, too.

Initial Evidence Of A Reduction In Malaria Incidence Following Indoor Residual Spraying With Actellic 300 Cs In A Setting With Pyrethroid Resistance: Mutasa District, Zimbabwe

Mufaro Kanyangarara and her PhD thesis adviser, Luke Mullany of the Johns Hopkins Bloomberg School of Public Health Department of International Health, have been looking into the challenges of controlling and eventually eliminating malaria in a multi-country context in southern Africa. We are sharing abstracts from her pioneering work including the following which explores indoor residual spraying in Zimbabwe in a District near the Mozambique border.

sprayed and unsprayed wardsIn order to reduce the vector population and interrupt disease transmission, IRS with appropriate insecticides is essential. In response to local vector resistance, the Zimbabwe NMCP with support from PMI began a large-scale IRS campaign with organophosphates in four high transmission districts in Manicaland province – Chimanimani, Mutare, Mutasa and Nyanga. Using HMIS data, the present study reports on the effect of switching from pyretheroids to OP on malaria morbidity in one of the four high transmission districts selected. In the subsequent high transmission season following the switch from pyretheroids to organophosphates, there was evidence of a 43% decline in malaria incidence reported by health facilities from wards in Mutasa District treated with organophosphates, after accounting for possible confounding by environmental variables. Previous research shows that switching to organophospates effectively reduced biting rates and vector densities in areas with pyretheroid resistant strains in Ghana, Benin and Tanzania. Although previous research focused on using entomological data to show the reduction in the vector population following application of Actellic, organophosphates, this study adds to the literature by showing a decline in malaria transmission using health facility surveillance data.

In the present study, there were variations in rainfall and temperature over the study period, and these changes were associated with changes in malaria incidence. The study results also indicated malaria transmission in Mutasa District was driven by rainfall, proximity to second order streams, elevation and temperature. These results concur with previous research, which found that elevation, temperature, and rainfall are positively associated with malaria incidence. After adjustment for climatic variables and seasonality, malaria incidence rates a downward trend following the 2014 IRS campaign and thus supporting the plausible conclusion that switching to organophosphates in this setting contributed to the observed public health benefits. No major political, socio-economic, or health-care changes with the potential to reduce malaria morbidity by almost half occurred in Mutasa District during the study period.

Observed and predicted weekly malaria counts in MutasaTypically data from health facilities only includes data on the number of suspected cases. The HMIS in Zimbabwe is more sophisticated in that it allows reports of confirmed malaria cases. In calculating of incidence rates, the denominator used was the catchment area population size. The reliability of this value has been questioned as this assumes that people will visit the closest health facility/health facility in their catchment area. It is noteworthy to mention that in the present study the main results did not chance after including an offset for catchment area population size. This indicates that in the Zimbabwean context, the reported catchment area population size may be a reliable estimate. The study also underscores the utility of HMIS data in the evaluation of population level interventions. The HMIS has the advantage of providing quality data quickly and easily, with minimal additional investment. Additionally, HMIS reflects the burden of disease on the health system. Results from this study further suggest that passive surveillance data from the HMIS in Zimbabwe was sufficiently sensitive to detect IRS related reduction in malaria morbidity among residents of Mutasa District.

There are several important limitations of this study that should be highlighted. Causal inferences between spraying and improvements in malaria incidence should be made with caution as spraying was not implemented as an intervention in a randomized control trial. However, data from 14 health facilities located in unsprayed wards were included in the analysis to serve as a comparison and help understand any possible changes in malaria morbidity unassociated with the 2014 IRS campaign. Although the univariate model indicated that health facilities in unsprayed wards carried a lower burden of malaria, the multivariable model showed no significant differences between health facilities in sprayed and unsprayed wards prior to the IRS pilot, suggesting that climatic variables included in the model adequately adjusted for differences. However, it should be noted that although the study adjusted for environmental factors, it did not account for other factors like population movement, changes in treatment seeking behaviors, changes in the coverage of ITNs during the study period. The model developed in this analysis assumed that these factors remained constant over the study period. This seems reasonable given that the rural population of Mutasa is relatively stable, with access to health facilities providing malaria diagnosis and treatment. Additionally, although the number of suspected malaria cases was not explicitly model, a descriptive analysis does not indicate changes in diagnostic practice over the study period (data not shown). The HMIS in Zimbabwe has been in place for decades and has previously been used to evaluate the impact of changes in malaria morbidity, construct empirical seasonality maps and describe the spatial and temporal distribution of malaria.

Despite these potential limitations, health surveillance systems provide a feasible and efficient means of collecting longitudinal data on measures of malaria morbidity. The pronounced decline in malaria morbidity observed in this study is evidence supporting the benefit of switching to an insecticide class with a different mode of action in response to pyretheroid resistance. Although the IRS strategy implemented by ZNMCP and PMI was successful, continued entomological monitoring will be necessary. Additionally, with emerging resistance to multiple insecticides, this approach may not be sustainable over time. There is need for the development of novel strategies to manage insecticide resistance.

World Mosquito Day Is Not Just About Malaria

World Mosquito Day Block the BiteOur colleagues at Roll Back Malaria remind is that 20 August is marked annually as World Mosquito Day since doctor Sir Ronald Ross first identified female Anopheles mosquitoes as the vector that transmits malaria between humans. This year, 2015 is the 118th annual observance.

It may seem obvious to state, but while malaria is carried by mosquitoes, not all types of mosquitoes carry malaria. And more specifically our control measures for combating the anopheles mosquitoes that carry malaria are not specifically aimed at aedes or culex. This has not stopped public health workers in the field, and health worker trainees in the classroom from broadcasting messages to the public implying that the control and destruction of any mosquito will prevent malaria.

In terms of health communication, if we convince people that any mosquito carries malaria, but institute measures like long lasting insecticide-treated nets and indoor residual spraying aimed at anopheles mosquitoes, we may lose some credibility as people will still see other types of mosquitoes flying about. And then when people develop another febrile illness from bites of those other mosquitoes, they may not differentiate illness types, but say our interventions do not work.

Old poster on malaria-mosquito presentionThe conflation of all mosquitoes with malaria is seen clearly in the image at the right from a common malaria poster. The dirty gutters may contain culex larvae; the cans and bottles may contain aedes larvae. Obviously none of these mosquito species is good for human health, so can we achieve clarity in health communication about mosquito-borne disease on World Mosquito Day and thereafter?

We often forget that people in the community are quite observant of their environment; sometimes more so the the public health inspectors who try to teach them about ways of preventing malaria by reducing mosquito breeding. Villagers deal with mosquitoes on a daily basis and can distinguish the coloring and posture of the different species.

Instead of telling people what to do, it would be more helpful for public health workers to engage in dialogue with people to learn what they know about different types of mosquitoes and different forms of febrile illness. Maybe by learning first from the people, health workers can then become better teachers about integrated vector management.

PS – maybe we can also educate the mass media to stop putting pictures of Aedes aegypti on their malaria stories!