Posts or Comments 17 October 2021

Archive for "Mosquitoes"



COVID-19 &Health Systems &Health Workers &Household &ITNs &Mosquitoes &Urban Bill Brieger | 16 Sep 2020

Malaria News Today 2020-09-16

Today we learn about malaria-carrying A. stephensi invading African cities, how malaria outpaces COVID-19 in Central African Republic, and the need to examine malaria service delivery in the context of strong health services. Malaria Journal looks at ITN use in Uganda and malaria genetic variability even at the household level. Click on links to read full articles.

Spread of city-loving malaria mosquitoes could pose grave threat to Africa

An Asian malaria-carrying mosquito that has adapted to urban life has the potential to spread to dozens of cities across the African continent, a new modeling study suggests.
The mosquito species, Anopheles stephensi, poses a serious new threat for African cities, says Francesca Frentiu, a geneticist at the Queensland University of Technology who was not involved in the research. She praises the work as “an important effort, underpinned by robust methods.” A. stephensi hopped from Asia to the Arabian Peninsula between 2000 and 2010 and then made another jump to the Horn of Africa; scientists first discovered it in Djibouti in 2012, then later in Ethiopia and Sudan.

In times of COVID-19, malaria remains the number one killer of children in CAR

Since the beginning of the year, MSF teams have treated 39,631 malaria cases in Batangafo, compared to 23,642 in the same period last year. The hospital in Batangafo – a town of 31,000 people, including 22,000 displaced from elsewhere in the Central African Republic – is bustling with activity. While a particular focus has been placed on infection prevention and control measures to identify and isolate people with suspected cases of COVID-19, another deadly disease has a much heavier impact on the lives of people living here.

September is the rainy season, when malaria becomes more deadly than ever in the Central African Republic each year. It is the leading cause of death for children under five in the country. During periods when malaria transmission is high, eight out of ten paediatrics consultations in the hospital supported by Médecins Sans Frontières (MSF) in Batangafo are due to complications from malaria, including anaemia and dehydration.

Assessment of health service delivery parameters in Kano and Zamfara States, Nigeria

In 2013, the Nigeria Federal Ministry of Health established a Master Health Facility List (MHFL) as recommended by WHO. Since then, some health facilities (HFs) have ceased functioning and new facilities were established. We updated the MHFL and assessed service delivery parameters in the Malaria Frontline Project implementing areas in Kano and Zamfara States.

In 2016, the US Centers for Disease Control and Prevention (CDC), in collaboration with the Nigeria National Malaria Elimination Program (NMEP), established a 3-year intervention project, Malaria Frontline Project (MFP), with the objectives of strengthening the technical capacity of LGA-level health workers, improving malaria surveillance and facilitating evidence-based decision-making. The project was implemented in Kano and Zamfara States.

Some deficiencies in the list of facilities in DHIS2 and MHFL were uncovered making it difficult to submit and access malaria program data. Also, some facilities were still using the old version of register which did not collect all indicators required by DHIS2. In addition there were a small number of non-functional facilities. Finally the low number of facilities within the PHC category meeting the minimum HR requirement will hamper the countries effort to achieve its goal of universal health coverage. From the foregoing, the study identifies several areas to improve delivery of malaria services specifically and universal coverage in general.

Individual, community and region level predictors of insecticide-treated net use among women in Uganda: a multilevel analysis

ITN use attributable to regional and community level random effects was 39.1% and 45.2%, respectively. The study has illustrated that ITN policies and interventions in Uganda need to be sensitive to community and region level factors that affect usage. Also, strategies to enhance women’s knowledge on malaria prevention is indispensable in improving ITN use.

Genetic diversity and complexity of Plasmodium falciparum infections in the microenvironment among siblings of the same household in North-Central Nigeria

These findings showed that P. falciparum isolates exhibit remarkable degree of genetic diversity in the micro-environment of the household and are composed mainly of multiclonal infections, which is an indication of a high ongoing parasite transmission. This suggests that the micro-environment is an important area of focus for malaria control interventions and for evaluating intervention programmes.

Climate &COVID-19 &Dengue &Diagnosis &Environment &Invest in Malaria Control &Mapping &mHealth &Migration &Mosquitoes &Nomadic People &Surveillance Bill Brieger | 11 Sep 2020

Malaria News Today 2020-09-11

Today’s news and abstracts look at a variety of issues ranging from overall malaria funding funding needs to the effect of climate change on different types of mosquitoes and the diseases they carry (e.g. malaria vs dengue). We also examine the need for surveillance among nomadic groups and the use of cell phones in a saliva based malaria testing system. Please click the links below to read more on each subject.

Rwanda: Government Needs U.S.$70 Million to Fill Malaria Financing Gap

By Nasra Bishumba: The Government needs $73 million to bridge the funding in the funds needed to fight malaria between 2020 and 2024, The New Times can reveal. The Rwanda National Strategic Plan 2020-2024 to fight malaria drawn up in June this year indicates that although the implementation requires Rwf295bn ($280 million), the government already has funding commitment to the tune of $206.8m (equivalent to 74 per cent).

According to the strategic plan, a copy of which The New Times has seen, this leaves a gap of $73m which it hopes to mobilize from different sources. With these funds, the government is seeking to protect at least 85 per cent of the population with preventive interventions and to work towards promptly testing and treating suspected malaria cases by 2024. To achieve this, the biggest chunk of the funds will be invested in malaria prevention to a tune of $186m, an equivalent of 66 per cent of the entire budget.

Climate Change May Shift Risks of Mosquito-borne Diseases

By Asher Jones: More dengue, less malaria. That may be the future in parts of Africa on a warming planet, depending on where you live. New research says it’s all about which mosquitoes will thrive. And the methods to control one don’t necessarily work on the other.

The mosquito that spreads malaria prefers relatively cool temperatures of 25 degrees Celsius (77 degrees Fahrenheit). The dengue mosquito does best at 29 degrees Celsius (84.2 degrees Fahrenheit). Because of this difference in optimal temperatures, “We would actually predict that climate change might have opposing effects [on disease transmission],” said Erin Mordecai, assistant professor of biology at Stanford University and lead author on the study. “Climate change might make it less suitable for malaria to be transmitted but more suitable for dengue to be transmitted.”

Africa’s Nomadic Pastoralists and Their Animals Are an Invisible Frontier in Pandemic Surveillance

@ASTMH The effects of COVID-19 have gone undocumented in nomadic pastoralist communities across Africa, which are largely invisible to health surveillance systems despite the fact that they are of key significance in the setting of emerging infectious disease. We expose these landscapes as a “blind spot” in global health surveillance, elaborate on the ways in which current health surveillance infrastructure is ill-equipped to capture pastoralist populations and the animals with which they coexist, and highlight the consequential risks of inadequate surveillance among pastoralists and their livestock to global health. As a platform for further dialogue, we present concrete solutions to address this gap.

Mobile phone-based saliva test wins NIH prize

Cornell researchers’ concept for a quick, non-invasive, mobile phone-based system to detect infectious diseases, inflammation and nutritional deficiencies in saliva was awarded a $100,000 National Institutes of Health Technology Accelerator Challenge prize. The NIH’s prize challenge encourages the development of new, non-invasive diagnostic technologies important for global health. For the group’s saliva-based test, a small 3D-printed adapter is clipped to a mobile phone and synced with a mobile app. The app uses the phone’s camera to image test strips to detect malaria, iron deficiency and inflammation, with results in under 15 minutes.

The proposal builds on the FeverPhone and NutriPhone platforms developed by the team at Cornell’s Institute for Nutritional Sciences, Global Health and Technology (INSiGHT). The technologies, funded by the NIH and the National Science Foundation, evaluate infections and nutritional status using blood. According to Mehta, technologies using salivary biomarkers could revolutionize how conditions such as malaria and iron deficiency are identified and addressed, especially in settings where access to primary health care and traditional, laboratory-based tests is limited.

Monsoon infections: How to tell the difference between dengue and malaria? Watch out for these symptoms

While both diseases are mosquito-borne and cause similar symptoms such as fever, joint/muscle pain, headaches, and fatigue, some differences between their symptoms can help you identify the specific infections. Unique symptoms of Malaria: Stomach problems such as vomiting, Diarrhoea, Dry cough, Shivering, Spleen enlargement Unique symptoms of Dengue: Pain behind the eyes, Swollen glands, Rashes

Coordination &COVID-19 &Ebola &Microscopy &Mosquitoes &Vector Control Bill Brieger | 04 Sep 2020

Malaria News Today 2020-09-04

Today, we are sharing more updates from newsletters and journal abstracts found online. Issues include citizens in Rwanda trapping mosquitoes, the need for standardizing microscopy, more information on Uganda’s Malaria fund, the challenge of containing three epidemics at once, an increase in cases in Namibia and genetic diversity of the parasite in Comoros. Click on links to read details.

Citizen science shows great potential to reduce malaria burden

A year-long collection of mosquitoes with self-made traps and over a hundred volunteers in rural Rwanda reporting levels of mosquito nuisance revealed when and where malaria risks were the highest. In addition to their reporting, the volunteers appeared to distribute knowledge and skills on controlling malaria within communities. Studies by Wageningen University & Research and the University of Rwanda show that citizen science has great potential to reduce the disease burden across the globe.

Uganda renews fight to eliminate malaria by 2030 – more on Malaria Free Uganda Fund

Uganda says it is fast-tracking efforts to eliminate malaria, which continues to take lives and bleed the country’s economy more than any other disease. The disease is responsible for 30 to 40 percent of outpatient hospital visits, 15 to 20 percent of admissions, and 10 percent of inpatient deaths, mostly pregnant mothers and children, according to the health ministry figures. The country on September 2 launched the board of directors of the Malaria Free Uganda Fund as part of its continued investment to eliminate the disease by 2030, as per the global target.

Malaria Free Uganda Fund is a nonprofit public-private partnership established to mainstream responsibility for malaria across all sectors and help remove financial and operational bottlenecks in fighting the disease. The National Malaria Control Program currently faces a three-year 206 U.S. million dollars budget gap, or 33 percent of the total, according to the ministry of health.  External donors, according to the ministry, fund over 95 percent of the fight against the disease in the country. The country is now looking at domestic resourcing in view of the global uncertainties like the COVID-19 pandemic that is affecting foreign financing. “The talent and experience we have mobilized to this board from the private and civil society will help the government achieve a significant reduction of malaria cases and deaths in Uganda,” said Ruth Aceng, minister of health while launching the board here.

Namibia records 12,507 malaria cases, 40 deaths in 2020

Namibia’s malaria cases this year increased to 12,507 from 2,841 recorded in 2019, according to statistics from the Ministry of Health. The southern African country recorded 31,000 cases of malaria in 2018. The National Vector-borne Diseases Control Program from the Health Ministry which monitors the weekly malaria situation in the country shows that this year alone 12,507 malaria cases where recorded, while 40 deaths occurred.

The ministry said the huge difference between 2019 and this year is attributed to the fact that 2019, was a drought year and the rainfall pattern was not similar to 2020 and 2018, hence the decline in malaria cases happened in 2019. According to the ministry, currently the implementation of the program activities amid COVID-19 is on halt due to some bottlenecks.

Congo sees increase in plague, at least 10 deaths this year

DR Congo is seeing an upsurge in cases of the plague, as the vast Central African nation also battles outbreaks of COVID-19 and Ebola. Since June, Congo has recorded at least 65 cases of the plague, including at least 10 deaths, in the eastern Ituri province according to Ituri provincial chief of health Dr. Louis Tsolu. While the plague is endemic in Ituri province, the number of cases is increasing and has already surpassed the total recorded in 2019 which had 48 cases and eight deaths, according to WHO.

Towards harmonization of microscopy methods for malaria clinical research studies

Microscopy performed on stained films of peripheral blood for detection, identification and quantification of malaria parasites is an essential reference standard for clinical trials of drugs, vaccines and diagnostic tests for malaria. The value of data from such research is greatly enhanced if this reference standard is consistent across time and geography. Adherence to common standards and practices is a prerequisite to achieve this. The rationale for proposed research standards and procedures for the preparation, staining and microscopic examination of blood films for malaria parasites is presented here with the aim of improving the consistency and reliability of malaria microscopy performed in such studies.

These standards constitute the core of a quality management system for clinical research studies employing microscopy as a reference standard. They can be used as the basis for the design of training and proficiency testing programmes as well as for procedures and quality assurance of malaria microscopy in clinical research.

Genetic diversity of Plasmodium falciparum in Grande Comore Island

Despite several control interventions resulting in a considerable decrease in malaria prevalence in the Union of the Comoros, the disease remains a public health problem with high transmission in Grande Comore compared to neighbouring islands. In this country, only a few studies investigating the genetic diversity of Plasmodium falciparum have been performed so far. For this reason, this study aims to examine the genetic diversity of P. falciparum by studying samples collected in Grande Comore in 2012 and 2013, using merozoite surface protein 1 (msp1), merozoite surface protein 2 (msp2) and single nucleotide polymorphism (SNP) genetic markers.

Artesunate &Dengue &Elimination &Malaria in Pregnancy &Mosquitoes &Nigeria &Resistance &Vector Control &Zika Bill Brieger | 03 Sep 2020

Malaria News Today 2020-09-03

Various updates were found in newsletters and journal abstracts online today. These looked at mosquitoes – what attracts them to people, how ookinetes move in the midgut, and how perlite from volcanic rock may be a barrier repellent. Nigeria reports that there is no ACT resistance – so far.  And malaria partners join to coordinate actions in Uganda.  Click on links to read details.

Nigeria yet to detect resistance of malaria parasite to ACTs, says ministe

Contrary to reports that Africa has for the first time identified resistance strain of the malaria parasite to the drug of choice, Artemisinin Combination Therapy (ACT), the Minister of Health, Dr. Osagie Emmanuel Ehanire, on Monday said a study conducted in three states of the country showed there is no such phenomenon in Nigeria.  “However, we are still monitoring the situation. We insist that people should conduct a malaria test before using the drug of choice. This we hope will help prevent any kind of resistance of the malaria parasite to ACTs.”

Ministry of Health launches the Malaria Free Uganda Fund

Health Minister Dr Jane Ruth Aceng told journalists in Kampala today that the idea of having this new board was reached after realizing that different entities have been conducting the same malaria control related work. She said that the ministry resolved that mainstreaming responsibility will remove financial and operational bottlenecks that deter them from achieving set targets for elimination of the disease. The fund with a board of 11 members is chaired by Kenneth Wycliffe Mugisha of the Rotarian Malaria Partners-Uganda.

Volcanic Rock Yields a New Kind of Insecticide for Mosquitoes

Insecticide resistance to pesticides has become widespread in mosquito populations, making insecticides less effective over time. Therefore, there is an urgent need for insecticides with alternative modes of action. tested a material derived from volcanic rock, perlite, as a potential non-chemical insecticide against Anopheles gambiae, one of the primary mosquitoes that spreads malaria in Africa. In their new report published in August in the Journal of Medical Entomology, they show that perlite has encouraging potential as a mechanical insecticide. Perlite is believed to act by causing dehydration in the mosquitoes. read more…

Mosquitoes love pregnant, beer-drinking exercisers with Type O blood

Mosquitoes spread Zika, West Nile, Chikungunya, Dengue, and Malaria, resulting in 700 million illnesses a year and a million deaths. Even if you don’t get sick from a mosquito bite, the blood thinner they pump into your flesh before draining your blood causes swelling and itching. This article in Smithsonian Magazine lists the factors that make some people more tempting targets than others to mosquito bites. They include:

  • Blood type: “One study found that in a controlled setting, mosquitoes landed on people with Type O blood nearly twice as often as those with Type A.”
  • Carbon Dioxide: “people who simply exhale more of the gas over time—generally, larger people—have been shown to attract more mosquitoes than others.”
  • Exercise: “mosquitoes find victims at closer range by smelling the lactic acid, uric acid, ammonia and other substances expelled via their sweat”
  • Skin bacteria: “scientists found that having large amounts of a few types of bacteria made skin more appealing to mosquitoes”
  • Beer: “Just a single 12-ounce bottle of beer can make you more attractive to the insects”
  • Pregnancy: “pregnant people exhale about 21 percent more carbon dioxide and are on average about 1.26 degrees Fahrenheit warmer than others”
  • Clothing color: “wearing colors that stand out (black, dark blue or red) may make you easier to find”
  • Genetics: “underlying genetic factors are estimated to account for 85 percent of the variability between people in their attractiveness to mosquitoes”

Live In Vivo Imaging of Plasmodium Invasion of the Mosquito Midgut

Malaria is one of the most devastating parasitic diseases in humans and is transmitted by anopheline mosquitoes. The mosquito midgut is a critical barrier that Plasmodium parasites must overcome to complete their developmental cycle and be transmitted to a new host. Here, we developed a new strategy to visualize Plasmodium ookinetes as they traverse the mosquito midgut and to follow the response of damaged epithelial cells by imaging live mosquitoes. Understanding the spatial and temporal aspects of these interactions is critical when developing novel strategies to disrupt disease transmission.

coronavirus &Dengue &Mortality &Mosquitoes Bill Brieger | 02 Sep 2020

Malaria News Today 2020-09-02

Updates from newsletters and journal abstracts found online today. Issues include health and malaria service disruptions from COVID-19, increased mosquito-borne diseases, including malaria, in India and mosquitoes and attractant odors. Click on links to read details.

Continuing vital health services in Guinea-Bissau during COVID-19

ReliefWeb explains that as lockdowns, curfews and transport disruptions prevent many vulnerable people from getting healthcare, communities are stepping into the breach. Community health workers and volunteers are ensuring their peers, friends, and neighbours are protected from disease. “In previous bednet distribution campaigns, we used to identify the families before setting up the distribution points,” said Ivannildo Vieira, a community health worker, “but this year, because of COVID-19 restrictions, it was decided to do door-to-door distributions in order not to gather people in a single distribution area.”

Helping communities protect themselves from diseases like malaria in Guinea-Bissau is no simple task. Located on West Africa’s coast, Guinea-Bissau is one of the world’s poorest and most fragile countries. Malaria is the leading cause of death among pregnant women and children under five. Malaria prevention measures have been complicated by a rapid increase in the number of COVID-19 cases.

Delhi records 24% rise in Dengue, Malaria in 7 days

While Delhi’s healthcare is overwhelmed with tackling the COVID-19 pandemic, another epidemic of vector-borne diseases are knocking at its door. A whopping rise of 24 per cent in Dengue, Malaria, and Chikungunya cases were recorded in the last one week.  The cities/corporations stated that they reported incidents of mosquito-breeding at 44,259 households and served 35,103 legal notices to the violators. Meanwhile, 1,512 prosecutions were launched against the violations.

Is Anopheles gambiae attraction to floral and human skin-based odours and their combination modulated by previous blood meal experience?

Malaria Journal notes that Mosquitoes use odours to find energy resources, blood hosts and oviposition sites. While these odour sources are normally spatio-temporally segregated in a mosquito’s life history, here this study explored to what extent a combination of flower- and human-mimicking synthetic volatiles would attract the malaria vector Anopheles gambiae sensu stricto (s.s.).

Nulliparous and parous A. gambiae s.s. are attracted to combinations of odours derived from spatio-temporally segregated resources in mosquito life-history (floral and human volatiles). This is favourable as mosquito populations are comprised of individuals whose nutritional and developmental state steer them to diverging odours sources, baits that attract irrespective of mosquito status could enhance overall effectiveness and use in monitoring and control. However, combinations of floral and skin odours did not augment attraction in semi-field settings, in spite of the fact that these blends activate distinct sets of sensory neurons. Instead, mosquito preference appeared to be modulated by blood meal experience from floral to a more generic attraction to odour blends. Results are discussed both from an odour coding, as well as from an application perspective.

Malaria Leaves 100 Dead in South Sudan

The East African reports that South Sudan’s Ministry of Health and the World Health Organization (WHO) say at least 100 people died of malaria in the  In a joint report released on Sunday, the two institutions said morbidity and mortality trends in the Protection of Civilians Sites across the country, as of July, indicated rampant deaths due to malaria infections.

IRS &Monkeys &Mosquitoes &Pharmacovigilence &Resistance &Vector Control Bill Brieger | 01 Sep 2020

Malaria News Today 2020-09-01

Today we feature summaries and abstracts concerning Plasmodium malariae, P. knowlesi and monkey models for vaccine testing, clothianidin insecticide resistance, the mosquito immune system and drug interactions between medicines for malaria patients.

Some mosquitoes already have resistance to the latest weapon against malaria

By Munyaradzi Makoni: An insecticide about to be widely deployed inside African homes to combat malaria-carrying mosquitoes is already losing its punch. Two years ago, the World Health Organization (WHO) gave the green light for clothianidin, long used in agriculture to kill crop pests, to be added to the current mainstays of indoor mosquito control, which are losing their effectiveness as the insects develop resistance. Since then, many African countries have been laying plans to spray the walls of homes with the pesticide—it would represent the first new class of chemicals adopted for such use in decades—and looking anxiously for evidence of pre-existing resistance.

Now, scientists at Cameroon’s Centre for Research in Infectious Diseases (CRID) have found it. They recently sampled mosquitoes from rural and urban areas around Yaoundé, the capital, including two key malaria carriers. In one standard susceptibility assay, exposure to clothianidin for 1 hour killed 100% of Anopheles coluzzii. But in some A. gambiae samples as many as 55% of the mosquitoes survived, the group reported in a preprint posted 7 August on the bioRxiv preprint server.

Atlas of Malaria Mosquitoes’ Immune System Assembled

An international team of scientists led by investigators at the Wellcome Sanger Institute and the NIH has created the first cell atlas of mosquito immune cells to understand how the insects fight malaria, as well as other mosquito-borne infections. The mosquito host is essential for the malaria parasite to complete its lifecycle, so any disruption would dramatically reduce the transmission of one of the world’s deadliest diseases.
Findings from the new study—published recently in Science through an article titled “Mosquito cellular immunity at single-cell resolution“—discussed the discovery of new types of mosquito immune cells, including a rare cell type that could be involved in limiting malaria infection. The authors also identified molecular pathways implicated in controlling the malaria parasite.

Genetic analysis of the orthologous crt and mdr1 genes in Plasmodium malariae from Thailand and Myanmar

Plasmodium malariae is a widely spread but neglected human malaria parasite, which causes chronic infections. The observed polymorphisms in pmcrt and pmmdr1 genes are unlikely to affect protein function and unlikely related to chloroquine drug pressure. Similarly, the absence of pmmdr1 copy number variation suggests limited mefloquine drug pressure on the P. malariae parasite population, despite its long time use in Thailand for the treatment of falciparum malaria.

Quantification of Plasmodium knowlesi versus Plasmodium falciparum in the rhesus liver: implications for malaria vaccine studies in rhesus models

Rhesus macaques are valuable pre-clinical models for malaria vaccine development. The Plasmodium knowlesi/rhesus and Plasmodium falciparum/rhesus models are two established platforms for malaria vaccine testing… Detection of 18S rRNA in the liver following high dose intravenous PfSPZ confirmed that rhesus are modestly susceptible to wild-type P. falciparum sporozoites. However, comparison of 18S rRNA RT-PCR biomarker signal indicates that the P. falciparum liver burden was 3–5 logs lower than in PkSPZ-infected animals. Quantification of this difference in liver stage burden will help guide and interpret data from pre-clinical studies of live-attenuated sporozoite vaccines in rhesus models.

Potential drug–drug interactions associated with adverse clinical outcomes and abnormal laboratory findings in patients with malaria

Hospitalized patients with malaria often present with comorbidities or associated complications for which a variety of drugs are prescribed. Multiple drug therapy often leads to drug–drug interactions (DDIs). The following drug pairs reported the highest frequency of adverse events associated with the interactions; calcium containing products-ceftriaxone, isoniazid–rifampin, pyrazinamide–rifampin, isoniazid–acetaminophen, and ciprofloxacin–metronidazole.

Children &Climate &COVID-19 &Diagnosis &Mosquitoes &Resistance Bill Brieger | 31 Aug 2020

Malaria News Today 2020-08-31

From time-to-time we will feature a collection of news and abstracts available “today.” Here are five stories available on 31st August 2020.

Med-tech on a leash: The many diseases that can be detected by dogs

Malaria, a parasitic disease, which is transmitted to humans by Anopheles mosquitoes, can also be detected by our canine friends. In 2019, English researchers presented the results of a study conducted in The Gambia, which involved training dogs with socks that had been worn by children infected with malaria, who otherwise had no symptoms.
The experiment proved to be so successful that researchers are now planning on using this method to test for asymptomatic cases of the disease….

New Malaria Transmission Patterns Emerge In Africa.

An international study reveals how future climate change could affect malaria transmission in Africa over the next century. Malaria is a climate sensitive disease; it thrives where it is warm and wet enough to provide surface water suitable for breeding by the mosquitoes that transmit it. For more than two decades now, scientists have suggested that climate change may alter the distribution and length of transmission seasons due to new patterns of temperature and rainfall. The burden of this disease falls primarily on Africa. In 2018, out of an estimated 228 million cases of malaria worldwide, 93% were in the African continent.
Detailed mapping of malaria transmission is vital for the distribution of public health resources and targeted control measures.

In the past, rainfall and temperature observations have been used in malaria climatic suitability models to estimate the distribution and duration of annual transmission, including future projections. But factors affecting how rainfall results in water for mosquito breeding are highly complex, for example how it is absorbed into soil and vegetation, as well as rates of runoff and evaporation. A new study, led by the Universities of Leeds and Lincoln in the UK, for the first time combined a malaria climatic suitability model with a continental-scale hydrological model that represents real-world processes of evaporation, infiltration and flow through rivers. This process-focused approach gives a more in-depth picture of malaria-friendly conditions across Africa….

Covid has spelt a lockdown for routine health services in India

Official data are now available to show the extent to which routine health services in India were unavailable and the scale of its impact. The number of fully immunised children fell by over 15 lakh in the three-month period from April to June compared to the same months last year. The number of institutional deliveries fell by about 13 lakh. The registered number of TB patients undergoing treatment fell to almost half of what it was last year. People seeking cancer treatment as outpatients fell by over 70%. Hard-won progress on several national health goals, including the programme to bring down infant and maternal mortality or those to treat TB, malaria and non-communicable diseases such as heart diseases, diabetes and cancer,

Insecticide resistance in indoor and outdoor-resting Anopheles gambiae in Northern Ghana

The overall results did not establish that there was a significant preference of resistant malaria vectors to solely rest indoors or outdoors, but varied depending on the resistant alleles present. Phenotypic resistance was higher in indoor than outdoor-resting mosquitoes, but genotypic and metabolic resistance levels were higher in outdoor than the indoor populations. Continued monitoring of changes in resting behaviour within An. gambiae s.l. populations is recommended.

Highlighting the burden of malarial infection and disease in the neonatal period: making sense of different concepts

Review of neonates from 14 malaria-endemic countries found pooled prevalence in this specific age group. Importantly, their results suggest a prevalence of congenital malaria of 40.4/1000, and a prevalence of neonatal malaria of 12/1000, Interestingly, the authors also confirmed congenital malaria to be more frequent in settings with unstable malaria transmission, a finding in line with the hypothesis of the importance of the immunity background in the risk of congenital malaria.

Epidemiology &History &Migration &Mosquitoes &Plasmodium/Parasite Bill Brieger | 12 Oct 2019

What to Observe on October 12th? Malaria’s Arrival in the Americas

Controversy exists about what historical event should be observed in the USA on 12th October. Ernest Faust explained many years ago that, “there is neither direct nor indirect evidence that the malaria parasites existed on this continent prior to the advent of the European conquerors,” while at the same time in the 16th through 18th Centuries, malaria was common in England, Spain, France, Portugal and other European nations that arrived in the “New World.” Initially, with the first voyage of Columbus the European explorers and settlers brought the disease, primarily Plasmodium vivax, while the slave trade brought P. falciparum.

National Geographic in its May 2007 issue provided the story “Jamestown, The Real Story.” This article reported that, “Colonists carried the plasmodium parasite to Virginia in their blood. Mosquitoes along the Chesapeake were ‘infected’ by the settlers and spread the parasite to other humans.” Thus malaria became one of many imported diseases that decimated the indigenous population. The spread of P. vivax in Jamestown was not surprising since the settlement was “located on marshy ground where mosquitoes flourished during the summer.”

Recent research has shown that the “Analysis of genetic material extracted showed that the American P. falciparum parasite is a close cousin of its African counterpart.” This research has documented two genetic groups in Latin America, related to two distinct slave routes run by the Spanish empire in the North, West Indies, Mexico and Colombia and the Portuguese empire to Brazil. Indigenous and remote rural populations of Bolivia, Colombia, Ecuador, Peru, Venezuela and Brazil remain at risk today.

In the South American continent the  native American population might have brought Melanesian strains of P. vivax before the Europeans arrived, but colonizers brought new strains from both Europe and Africa, as well as P. falciparum. Clearly, human migration has played an important role in malaria parasite dissemination through the Americas.

But back to the North American Continent where the USA is observing the historical implications of 12th October, Mark Blackmore reminds us that, “Anthropological and archeological data provide no indication of mosquito-borne diseases among the indigenous people of North America prior to contact with Europeans and Africans beginning in the fifteenth century” (Wing Beats Volume 25 Winter 2015). The spread of malaria by European colonizers is certainly not something to celebrate today.

Asymptomatic &Elimination &Eradication &Monkeys &Mosquitoes &Resistance &Vaccine Bill Brieger | 23 Aug 2019

Biology and Malaria Eradication: Are there Barriers?

During a press conference prior to the release of the executive summary of 3-year study of trends and future projections for the factors and determinants that underpin malaria by its Strategic Advisory Group on Malaria Eradication (SAGme), WHO outlined some hopeful signs emanating from the SAGme including

  1. Lack of biological barriers to malaria eradication
  2. Recognition of the massive social and economic benefits that would provide a return on investment in eradication, and
  3. Megatrends in the areas of factors such as land use, climate, migration, urbanization that could inhibit malaria transmission

Concerning the first point, the executive summary notes that, “We did not identify biological or environmental barriers to malaria eradication. In addition, our review of models accounting for a variety of global trends in the human and biophysical environment over the next three decades suggest that the world of the future will have much less malaria to contend with.”

The group did agree that, “using current tools, we will still have 11 million cases of malaria in Africa in 2050.” So one wonders whether there are biological barriers or not.

Interestingly the group did identify, “Potential biological threats to malaria eradication include development of insecticide and antimalarial drug resistance, vector population dynamics and altered vector behaviour. For example, Anopheles vectors might adapt to breeding in polluted water, and mosquito vector species newly introduced to Africa, such as Anopheles stephensi, could spread more widely into urban settings.”

This discussion harkens back to an important conceptual article by Bruce Aylward and colleagues that raised the question in the American Journal of Public Health, “When Is a Disease Eradicable?” They outlined three important criteria that had been proposed at two international conferences in 1997 and 1998.

  1. biological and technical feasibility
  2. costs and benefits, and
  3. societal and political considerations

Their further expansion on the biological issues using smallpox as an example is instructive. They noted that not only are humans essential for the life cycle of the organism, but that there was no other reservoir for the causative virus, and the virus could not amplify in the environment. In short, there were no vectors, as in the case of malaria. The relatively recent documentation of transmission of malaria between humans and other primates of different plasmodium species is another biological concern. At this point, Malaysia, for example, is reporting more cases of Plasmodium knowlesi in humans that either P vivax or P falciparum.

Another biological issue identified by Aylward and colleagues was the fact that smallpox had one effective and proven intervention, the vaccine. Application of the vaccine could be targeted using photograph disease recognition cards as the signs were quite specific to the disease. Malaria has several effective interventions, but most strategies emphasize the importance of using a combination of these, and implementation is met with a number of management and logistical challenges. The signs and symptoms of malaria are confused with a number of febrile illnesses.

Finally, two other issues raised concern. Insecticide resistance was recognized in the first malaria eradication effort, and is raising its head again, as pointed out by SAGme. Comparing smallpox and yaws, the challenge of latent or sub-clinical/asymptomatic infection was mentioned. Malaria too, is beleaguered with this problem.

Clearly, we must not lose momentum in the marathon (not a race) to eliminate malaria, but we must, as WHO stressed at the press conference, increase our research and development efforts to strengthen existing tools and develop new once to address the biological and logistical challenges.

Borders &Diagnosis &Ebola &Elimination &Integrated Vector Management &ITNs &Mosquitoes &NTDs &Snakebite &Trachoma &Urban Bill Brieger | 04 Aug 2019

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.

« Previous PageNext Page »