Asymptomatic <i>Plasmodium falciparum</i> carriage at the end of the dry season is associated with subsequent infection and clinical malaria in Eastern Gambia

Background: Chronic carriage of asymptomatic low-density Plasmodium falciparum parasitaemia in the dry season may support maintenance of acquired immunity that protects against clinical malaria. However, the relationship between chronic low-density infections and subsequent risk of clinical malaria episodes remains unclear. Methods: In a 2-years study (December 2014 to December 2016) in eastern Gambia, nine cross-sectional surveys using molecular parasite detection were performed in the dry and wet season. During the 2016 malaria transmission season, passive case detection identified episodes of clinical malaria. Results: Among the 5256 samples collected, 444 (8.4%) were positive for P. falciparum. A multivariate model identified village of residence, male sex, age ≥ 5 years old, anaemia, and fever as independent factors associated with P. falciparum parasite carriage. Infections did not cluster over time within the same households or recurred among neighbouring households. Asymptomatic parasite carriage at the end of dry season was associated with a higher risk of infection (Hazard Ratio, HR = 3.0, p &lt; 0.0001) and clinical malaria (HR = 1.561, p = 0.057) during the following transmission season. Age and village of residence were additional predictors of infection and clinical malaria during the transmission season. Conclusion: Chronic parasite carriage during the dry season is associated with an increased risk of malaria infection and clinical malaria. It is unclear whether this is due to environmental exposure or to other factors.</p

Asymptomatic <i>Plasmodium falciparum</i> carriage at the end of the dry season is associated with subsequent infection and clinical malaria in Eastern Gambia

BACKGROUND: Chronic carriage of asymptomatic low-density Plasmodium falciparum parasitaemia in the dry season may support maintenance of acquired immunity that protects against clinical malaria. However, the relationship between chronic low-density infections and subsequent risk of clinical malaria episodes remains unclear.METHODS: In a 2-years study (December 2014 to December 2016) in eastern Gambia, nine cross-sectional surveys using molecular parasite detection were performed in the dry and wet season. During the 2016 malaria transmission season, passive case detection identified episodes of clinical malaria.RESULTS: Among the 5256 samples collected, 444 (8.4%) were positive for P. falciparum. A multivariate model identified village of residence, male sex, age ≥ 5 years old, anaemia, and fever as independent factors associated with P. falciparum parasite carriage. Infections did not cluster over time within the same households or recurred among neighbouring households. Asymptomatic parasite carriage at the end of dry season was associated with a higher risk of infection (Hazard Ratio, HR = 3.0, p &lt; 0.0001) and clinical malaria (HR = 1.561, p = 0.057) during the following transmission season. Age and village of residence were additional predictors of infection and clinical malaria during the transmission season.CONCLUSION: Chronic parasite carriage during the dry season is associated with an increased risk of malaria infection and clinical malaria. It is unclear whether this is due to environmental exposure or to other factors.</p

A Cohort Study on the Duration of Plasmodium falciparum Infections During the Dry Season in The Gambia.

BACKGROUND: In areas where Plasmodium falciparum malaria is seasonal, a dry season reservoir of blood-stage infection is essential for initiating transmission during the following wet season. METHODS: In The Gambia, a cohort of 42 individuals with quantitative polymerase chain reaction-positive P falciparum infections at the end of the transmission season (December) were followed monthly until the end of the dry season (May) to evaluate infection persistence. The influence of human host and parasitological factors was investigated. RESULTS: A large proportion of individuals infected at the end of the wet season had detectable infections until the end of the dry season (40.0%; 16 of 40). At the start of the dry season, the majority of these persistent infections (82%) had parasite densities >10 p/µL compared to only 5.9% of short-lived infections. Persistent infections (59%) were also more likely to be multiclonal than short-lived infections (5.9%) and were associated with individuals having higher levels of P falciparum-specific antibodies (P = .02). CONCLUSIONS: Asymptomatic persistent infections were multiclonal with higher parasite densities at the beginning of the dry season. Screening and treating asymptomatic infections during the dry season may reduce the human reservoir of malaria responsible for initiating transmission in the wet season

‘Some anti-malarials are too strong for your body, they will harm you.’ Socio-cultural factors influencing pregnant women’s adherence to anti-malarial treatment in rural Gambia

Background Despite declining prevalence of malaria in The Gambia, non-adherence to anti-malarial treatment still remains a challenge to control efforts. There is limited evidence on the socio-cultural factors that influence adherence to anti-malarial treatment in pregnancy. This study explored perceptions of malaria in pregnancy and their influence on adherence to anti-malarial treatment in a rural area of The Gambia. Methods An exploratory ethnographic study was conducted ancillary to a cluster-randomized trial on scheduled screening and treatment of malaria in pregnancy at village level in the Upper River Region of The Gambia from June to August 2014. Qualitative data were collected through interviewing and participant observation. Analysis was concurrent to data collection and carried out using NVivo 10. Results Although women had good bio-medical knowledge of malaria in pregnancy, adherence to anti-malarial treatment was generally perceived to be low. Pregnant women were perceived to discontinue the provided anti-malarial treatment after one or 2 days mainly due to non-recognition of symptoms, perceived ineffectiveness of the anti-malarial treatment, the perceived risks of medication and advice received from mothers-in-law. Conclusion Improving women’s knowledge of malaria in pregnancy is not sufficient to assure adherence to anti-malarial treatment. Addressing structural barriers such as unclear health workers’ messages about medication dosage, illness recognition, side effects of the medication and the integration of relatives, especially the mothers-in-law, in community-based programmes are additionally required

Fear and rumours regarding placental biopsies in a malaria-in-pregnancy trial in Benin.

BACKGROUND: A multi-country, community-based trial on scheduled screening and treatment for malaria in pregnancy was conducted in Benin, The Gambia and Burkina Faso. Despite standardized procedures and outcomes, the study became subject to rumours and accusations of placenta being sold for mystical and financial gain by trial staff, leading to drop-out rates of 30% and the consequent halting of placental biopsy sampling in Benin. This paper explores the role of socio-cultural beliefs related to placenta and identified additional factors contributing these rumours. METHODS: A qualitative comparative emergent-theory design was used to assess social factors related to trial implementation and uptake in the three countries. Data from participant observation, informal conversations, group discussions and interviews were triangulated and analysed with NVivo Qualitative Analysis software. RESULTS: Despite similar sociocultural beliefs about the sacred nature of the placenta in all three study countries, these beliefs did not affect participation rates in Burkina Faso and The Gambia and placenta-related rumours only emerged in Benin. Therefore, the presence of beliefs is not a sufficient condition to have generated placenta-selling fears. The rumours in Benin reflected the confluence of placenta-related beliefs and factors related to the implementation of the trial (including a catalysing adverse event and miscommunication during the informed consent procedure). Furthermore, distinct socio-political factors contributed to the emergence of rumours, including the historical distrust in governmental organizations and the tense relationship between some of the actors involved in the trial. CONCLUSION: Transdisciplinary social science research designs should accompany the implementation of the trial. The integration of multiple stakeholders' knowledge and involvement is required to define and solve upcoming barriers