Tropical Health Matters

As part of the activities in the course Social and Behavioral Foundations of Primary Health Care, class members write a blog on a current health issue. Amr Marawan has shared the context of schistosomiasis control in Nigeria on the class blog. His writing is reposted below and can also be read along with those of his classmates in the SBFPHC Blog site.

Schistosomiasis was described in papyrus papers thousands of years ago by ancient Egyptians. Then it was re-described by Theodore Bilharz, a pioneer parasitologist, 150 years ago in Cairo, Egypt. Schistosomiasis is among a group of neglected tropical diseases hitting sub-Saharan Africa. There are more than 25 million individuals infected and more than 100 million at risk in Nigeria. Among the different types of schistosomiasis, Schistosoma Haematobium affects the urogenital system causing blood in the urine and other symptoms and predisposes to urinary cancer.

photo source: http://www.bio.davidson.edu/people/midorcas/GISclass/GISwebsites/grayson/Schistosomiasis.htm

Despite the global efforts over the past 50 years, we only achieved limited success in Nigeria. Most of the campaigns designed used Praziquantel for prevention and treatment, as it has shown great success in multiple countries. Unlike other previously endemic states, the use of chemotherapy was not sufficient to address this major problem in Nigeria due to several limitations. In 2012. The World Health Organization (WHO) and World Health Assembly (WHA) adopted a multifaceted plan to eradicate schistosomiasis. The plan aims at strengthening the local health systems, using chemotherapy, appropriate sanitation, and water systems, as well as promoting hygiene education and snail control. There will be multiple designs for this approach to address the different challenges in the different states.

In order to succeed in this battle, all the stakeholders should cooperate and understand their role. The Federal ministry of health in Nigeria should communicate and supervise the local communities closely to ensure that there is no waste of resources. The pharmaceutical companies play a fundamental role by supplying millions of praziquantel pills with the help of non-governmental organizations (such as the Carter Center). The schools and religious leaders should educate the citizens about this disease and the role of both chemotherapy and sanitation to lead a healthy and productive life. The local community leaders are responsible for maintaining the momentum to achieve the utmost benefit for their people in spite of the conflicting perception for this campaign.

Six years after the WHA declaration, there was a substantial success demonstrated by treating approximately 75 % of school aged children. There is a new road map issued by the WHO for the tropical diseases for 2021-2030 to address the gaps and finish the incomplete mission.

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.

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.

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.

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.