Category Archives: Anemia

Malaria News Today 2020-09-18/19

Several reports and studies aim to help understand the malaria parasite and the human behavior surrounding its control. Cultural perceptions in Benin influence treatment seeking. Tracking cases in India aid in elimination efforts. The contrasts between in vivo and in vitro studies are examined. The factors associated with anemia among children and women in Ghana are traced to malaria and other factors. Finally both human and mosquito immunity are discussed. Click the links in each section to read details.

Demonstration of indigenous malaria elimination through Track-Test-Treat-Track (T4) strategy in a Malaria Elimination Demonstration Project in Mandla, Madhya Pradesh

Using the current intervention and prevention tools along with optimum utilization of human resources,This project has revealed about 91% reduction of indigenous cases of malaria during the period from June 2017 to May 2020, through case management and vector control strategies. A total 357,143 febrile cases were screened, out of which 0.19% were found positive.

The reduction was similar in the three high prevalence blocks of the district. These results reveal that malaria elimination is achievable in India within a stipulated time frame. The reduction of malaria at the community level was further validated when zero malaria cases were diagnosed during hospital and community-based studies in Mandla. Prompt detection and treatment of imported/migratory cases may have prevented outbreaks in the district. This project has demonstrated that field programmes backed by adequate technical, management, operational, and financial controls with robust monitoring are needed for achieving malaria elimination.needed for achieving malaria elimination.

Risk factors for anaemia among Ghanaian women and children vary by population group and climate zone

Anaemia has serious effects on human health and has multifactorial aetiologies. This study aimed to determine putative risk factors for anaemia in children 6-59 months and 15- to 49-year-old non-pregnant women living in Ghana. Data from a nationally representative cross-sectional survey were analysed for associations between anaemia and various anaemia risk factors. National and stratum-specific multivariable regressions were constructed separately for children and women to calculate the adjusted prevalence ratio (aPR) for anaemia of variables found to be statistically significantly associated with anaemia in bivariate analysis. Nationally, the aPR for anaemia was greater in children with iron deficiency (ID; aPR 2.20; 95% confidence interval [CI]: 1.88, 2.59), malaria parasitaemia (aPR 1.96; 95% CI: 1.65, 2.32), inflammation (aPR 1.26; 95% CI: 1.08, 1.46), vitamin A deficiency (VAD; aPR 1.38; 95% CI: 1.19, 1.60) and stunting (aPR 1.26; 95% CI: 1.09, 1.46).

In women, ID (aPR 4.33; 95% CI: 3.42, 5.49), VAD (aPR 1.61; 95% CI: 1.24, 2.09) and inflammation (aPR 1.59; 95% CI: 1.20, 2.11) were associated with anaemia, whereas overweight and obese women had lower prevalence of anaemia (aPR 0.74; 95% CI: 0.56, 0.97). ID was associated with child anaemia in the Northern and Middle belts, but not in the Southern Belt; conversely, inflammation was associated with anaemia in both children and women in the Southern and Middle belts, but not in the Northern Belt. Anaemia control programmes should be region specific and aim at the prevention of ID, malaria and other drivers of inflammation as they are the main predictors of anaemia in Ghanaian children and women.

From Circulation to Cultivation: Plasmodium In Vivo versus In Vitro

Research on Plasmodium parasites has driven breakthroughs in reducing malaria morbidity and mortality. Standard in vitro culture environments differ dramatically from in vivo conditions in nutrient levels, hematocrit, and rheology and have lower variability in gas levels and temperature.

Nutritional and physical differences lead to pronounced, and often rapid, changes in phenomenon, important for understanding virulence in Plasmodium. Parasite drug sensitivity may be altered due to culture adaptation selection, supraphysiological metabolite concentrations, and in vitro media formulations. Parasites propagated in vitro, versus in vivo, show altered transcriptomic and genomic patterns related to virulence factors, metabolism, gametocytogenesis, and more.

Direct-from-host methodologies avoid the impacts of in vitro culture adaptation but limit the types of assessments that can be performed as many experiments either require equipment not readily available in endemic settings or necessitate long-term manipulation….

Between traditional remedies and pharmaceutical drugs: prevention and treatment of “Palu” in households in Benin, West Africa

In Benin, malaria clinical cases, including the larger popular entity called “Palu” are evoked when people get fever. “Palu” is often self-diagnosed and self-medicated at home. This study aimed to describe the use of herbal medicine, and/or pharmaceutical medicines for prevention and treatment of malaria at home and the factors associated with this usage.

Methods. A cross-sectional survey was conducted in Benin in an urban and in a rural area in 2016. Around 600 households in each place were selected by using a random sampling of houses GPS coordinates of the families. The association between socio demographic characteristics and the use of herbal medicine was tested by using logistic regression models.

Results. In Cotonou (urban), 43.64% of households reported using herbal or pharmaceutical medicine to prevent “Palu”, while they were 53.1% in Lobogo (rural). To treat “Palu” in Cotonou, 5.34% of households reported using herbal medicine exclusively, 33.70% pharmaceutical medicine exclusively and 60.96% reported using both. In Lobogo, 4% reported using herbal medicine exclusively, 6.78% pharmaceutical medicine exclusively and 89.22% reported using both. In Cotonou, the factors “age of respondent”, “participation to a traditional form of savings” and “low socioeconomic level of the household” were associated with the use of herbal medicine.

Conclusions. This study shows the strong use of herbal medicine to prevent “Palu” or even treat it, and in this case it is mostly associated with the use of pharmaceutical medicine. It also highlights the fact that malaria control and care seeking behaviour with herbal medicine remain closely linked to household low-income status but also to cultural behaviour. The interest of this study is mostly educational, with regards to community practices concerning “Palu”, and to the design of adapted behaviour change communication strategies. Finally, there is a need to take into account the traditional habits of populations in malaria control and define a rational and risk-free use of herbal medicine as WHO-recommended.

Malaria parasite fools body with protein to dodge immune system

By SHIGEKO SEGAWA: OSAKA- The parasite responsible for malaria generates a look-alike of a human protein to suppress the workings of the immune system, leaving humans “defenseless” against infection, according to Japanese and British researchers.
A team comprised mainly of researchers from Osaka University and the University of Oxford said they hope the finding will help lead to new therapies for the mosquito-borne tropical disease.

As plasmodium is resistant to the immune system, the body’s self-defense system, humans can become infected repeatedly. Three years ago, the researchers realized that when plasmodium infects human red blood cells, it generates proteins called RIFINs, which send out signals for suppressing immunity. During the latest study, the researchers analyzed the structure of RIFIN in detail and found it closely resembles part of the structure of a specific human protein, which is involved in the mechanism for preventing the immune system from staging an attack on the body by mistake.

That protein combines with a molecule that suppresses the workings of the immune system. The scientists found the RIFIN that closely imitates the human protein in shape also combines with the same molecule and dodges attacks of the immune system. “We hope our findings will help develop vaccines and therapeutic drugs for malaria,” said Hisashi Arase, a professor of immunology with Osaka University, who is part of the research team. The research results were published in Nature, the British scientific journal.

Why Do Insect Vectors Not Get Ill from the Microbes They Transmit?

Some Evidence from Malaria-carrying Mosquitos by Kevin Noonan. The conservation of diverse and molecularly well-defined hemocyte types between distantly related mosquito genera and the apparent absence of megacytes in our Ae. aegypti mosquito dataset raise questions as to how the immune systems of these mosquito species have evolved to limit their capacity to transmit parasites and arboviruses to humans. This knowledge will ultimately underpin immunological strategies aimed at interrupting disease transmission by rendering mosquitoes resistant to such pathogens.

The conservation of diverse and molecularly well-defined hemocyte types between distantly related mosquito genera and the apparent absence of megacytes in our Ae. aegypti mosquito dataset raise questions as to how the immune systems of these mosquito species have evolved to limit their capacity to transmit parasites and arboviruses to humans. This knowledge will ultimately underpin immunological strategies aimed at interrupting disease transmission by rendering mosquitoes resistant to such pathogens.

NTD News Today 2020-09-09 from ASTMH

The current table of contents from the American Journal of Tropical Medicine and Hygiene features several important articles on neglected tropical diseases and malaria. Below are abstracts of several with links to the journal.

Agent-Based Simulation for Seasonal Guinea Worm Disease in Chad Dogs

The campaign to eradicate dracunculiasis (Guinea worm [GW] disease) and its causative pathogen Dracunculus medinensis (GW) in Chad is challenged by infections in domestic dogs, which far outnumber the dwindling number of human infections. We present an agent-based simulation that models transmission of GW between a shared water source and a large population of dogs. The simulation incorporates various potential factors driving the infections including external factors and two currently used interventions, namely, tethering and larvicide water treatments.

By defining and estimating infectivity parameters and seasonality factors, we test the simulation model on scenarios where seasonal patterns of dog infections could be driven by the parasite’s life cycle alone or with environmental factors (e.g., temperature and rainfall) that could also affect human or dog behaviors (e.g., fishing versus farming seasons).

We show that the best-fitting model includes external factors in addition to the pathogen’s life cycle. From the simulation, we estimate that the basic reproductive number, R 0, is approximately 2.0; our results also show that an infected dog can transmit the infection to 3.6 other dogs, on average, during the month of peak infectivity (April). The simulation results shed light on the transmission dynamics of GWs to dogs and lay the groundwork for reducing the number of infections and eventually interrupting transmission of GW.

Village Response to Mass Drug Administration for Schistosomiasis in Mwanza Region, Northwestern Tanzania

Are We Missing Socioeconomic, Cultural, and Political Dimensions?

Praziquantel (PZQ)-based mass drug administration (MDA) is the main approach for controlling schistosomiasis in endemic areas. Interventions such as provision and use of clean and safe water, minimizing contacts with infested water, disposal of human waste in latrines, and snail control provide additional key interventions to break the transmission cycle and could complement and perhaps sustain the benefits of MDA. However, all interventions deployed need to be accepted by the targeted communities. A qualitative study was conducted to examine factors that might differentiate villages which did not show a substantial decrease in Schistosoma mansoni prevalence despite repeated, high treatment coverage referred to as “persistent hotspot villages” from villages which showed a substantial decrease in prevalence referred to as “responding (RES) villages.” A convenient sample of adults was drawn from eight villages. Thirty-nine key informants were interviewed and 16 focus groups were held with a total of 123 participants. Data were analyzed manually using a thematic content approach. In both hotspot and RES villages, schistosomiasis was not considered to be a priority health problem because of its chronic nature, lack of knowledge and awareness, and poverty among study communities.

Hotspot villages exhibited poor leadership style, lack of or insufficient social engagement, little or lack of genuine community participation, little motivation, and commitment to schistosomiasis control compared with RES villages where there were commitment and motivation to fight schistosomiasis. We support the view of scholars who advocate for the adoption of a biosocial approach for effective and sustainable PZQ-based MDA for schistosomiasis control.

Assessment of Incubation Period of Cutaneous Leishmaniasis due to Leishmania major in Tunisia

The period between the infective sandfly bites and appearance of cutaneous leishmaniasis (CL) lesions is still hypothetical and little studied. This work aimed at assessing the incubation time of zoonotic CL (ZCL) due to Leishmania major using a standardized methodology. The retrospective analysis used the epidemiological, clinical, and biological information available in the database recording all the CL cases diagnosed at the Parasitology Department of the Pasteur Institute of Tunis during 2015–2019. It allowed for the selection of 92 privileged observations 1) of confirmed CL cases with presentation suggestive of ZCL form 2) living in northern regions free of ZCL 3) with a single infective trip of less than a week to ZCL foci during transmission season and 4) with accurate dates of travel and onset of lesions. Incubation length computed in this population ranged from 1 to 21 weeks, with a median of 5 weeks (interquartile range: 3–8.5 weeks).

Schistosoma mansoni Vector Snails in Antigua and Montserrat

Snail-Related Considerations Pertinent to a Declaration of Elimination of Human Schistosomiasis.

Investigations leading to a WHO-validated declaration of elimination of schistosomiasis transmission are contemplated for several countries, including Caribbean island nations. With assistance from the Pan American Health Organization, we undertook freshwater snail surveys in two such nations, Antigua and Barbuda, and Montserrat in September and October 2017. Historically, the transmission of Schistosoma mansoni supported by the Neotropical vector snail Biomphalaria glabrata occurred in both countries. Transmission on the islands is thought to have been interrupted by the treatment of infected people, improved sanitation, introduction of competitor snails, and on Montserrat with the eruption of the Soufrière volcano which decimated known B. glabrata habitats. Guided by the available literature and local expertise, we found Biomphalaria snails in seven of 15 and one of 14 localities on Antigua and Montserrat, respectively, most of which were identified anatomically and molecularly as Biomphalaria kuhniana.

Two localities on Antigua harbored B. glabrata, but no schistosome infections in snails were found. For snail-related aspects of validation of elimination, there are needs to undertake basic local training in medical malacology, be guided by historical literature and recent human schistosomiasis surveys, improve and validate sampling protocols for aquatic habitats, enlist local expertise to efficiently find potential transmission sites, use both anatomical and molecular identifications of schistosomes or putative vector snail species found, if possible determine the susceptibility of recovered Biomphalaria spp. to S. mansoni, publish survey results, and provide museum vouchers of collected snails and parasites as part of the historical record.

Decreased Mortality of falciparum Malaria in Anemic Prisoners of War?

Modern clinical trials have suggested that anemia protects against malaria mortality. Military records of the Second World War in Asia were examined to see if there was support for this hypothesis. When relatively well-nourished Imperial Japanese Navy sailors captured on Nauru (n = 799) were imprisoned on the Fauro Islands, 26% died from falciparum malaria. Similarly treated but very malnourished colocated Imperial Army soldiers experienced low stable malaria mortality. One-fifth of previously healthy Australian Army soldiers (n = 252) retreating from New Britain died largely because of malaria in April 1942. Malnourished prisoners of war, who were as a group very anemic, both Australian Army soldiers in Thailand and Japanese Army soldiers in Papua New Guinea, had high malaria rates but very low (< 3%) mortality rates. Malaria immunity does not adequately explain this dichotomy, suggesting that severe nutritional deprivation may be protective against malaria mortality possibly because of iron-deficiency anemia.

Anemia: another place to focus on integration within antenatal care

Anemia in pregnancy is responsible not only for threats to a woman’s health, but ultimately the survival of the child. Hotez and Molyneux in a PLoS Neglected Tropical Diseases editorial explain that …

“… most of the 7.5 million pregnant women infected with hookworm likely live in areas of sub-Saharan Africa that place them at risk for malaria. At the same time, malaria control and NTD control have each been shown to reduce anemia both in children and in pregnant women. Therefore, combining malaria and NTD control practices in a unified anemia framework affords one of the best opportunities to reduce the huge burden of morbidity and mortality that results from anemia in sub-Saharan Africa.”

detect-and-prevent-anemia-in-pregnancy2.jpgEach disease presents its own challenges. Guyatt and Snow report that, “Although the vast majority of women with malaria infections during pregnancy remain asymptomatic, infection increases the risk of maternal anemia and delivering a low-birth-weight (LBW) baby.” Furthermore, “It is estimated that in areas where malaria is endemic, around 19% of infant LBWs are due to malaria and 6% of infant deaths are due to LBW caused by malaria. These estimates imply that around 100,000 infant deaths each year could be due to LBW caused by malaria during pregnancy in areas of malaria endemicity in Africa.”

Addressing hookworm during pregnancy in Peru, Larocque and colleagues found that pregnant women, “infected with moderate and heavy intensities of hookworm infection and those with moderate and heavy intensities of both hookworm and Trichuris infections were more likely to suffer from anemia than women having no or light intensities. These results support routine anthelminthic treatment within prenatal care programs in highly endemic areas.”

Positive experiences on anthelminthic control were also reported from Nepal in the Lancet. During prenatal care  “… women received albendazole twice during pregnancy. Women given albendazole in the second trimester of pregnancy had a lower rate of severe anaemia during the third trimester. Birthweight of infants of women who had received two doses of albendazole rose by 59 g , and infant mortality at 6 months fell by 41%. Antenatal anthelmintics could be effective in reducing maternal anaemia and improving birthweight and infant survival in hookworm-endemic regions.”

We reported from Mozambique that PMTCT and IPTp for malaria in pregnancy control are integrated into antenatal care in many clinics.  One can see metronidazole in addition to SP and AZT in the picture among the preventive medicines available for pregnant women. Countries can make their choices of anthelminthics, including albendazole, but the meassage that Hotez and Molyneux convey is the need to control NTDs like soil transmitted helminths should be an integral part of services for pregnant women.