Community perspectives on treating asymptomatic infections for malaria elimination in The Gambia

This mixed methods study was carried out in the North Bank Region of The Gambia. The main ethnic groups residing in these villages are Fula, Mandinka and Wollof, although there are other minority groups: Bambara, Tilibonka and Turkas, that migrated from neighbouring Mali and Burkina Faso. Most are Muslims. Each ethnic group speaks their own language, although Mandinka or Fula is the common language for communication and trade. Farming is the most common occupation, with peanuts as the main cash crop, while rice, maize, beans, and vegetables are grown for own consumption. A significant number of families supplement their income through remittances from relatives living either in the major towns or abroad.

Malaria transmission in the area is seasonal, low (transmission prevalence of 5%) and occurs mostly between July and December. The main malaria parasite is Plasmodium falciparum [35].

The trial was a cluster-randomized trial designed to assess the impact of reactive treatment of contacts of a clinical malaria case living in the same compound on the prevalence of malaria infection at the end of the transmission season. It was planned over two transmission seasons. In the first season (preparatory phase), study villages (17 intervention, 17 control) were identified and approaches to integrate the intervention into the communities and health system were tested and adapted by social scientists and health system researchers through formative research. During this process, trial implementation concerns were identified and solutions co-developed with relevant stakeholders, including community members, health service providers and policy makers. The final health messages for sensitization, including the medicine distribution strategy involving key community actors such as village health workers (VHWs) and compound heads developed for community members to support the intervention, were applied in all intervention villages in the second season (implementation phase).

In the qualitative study, sampling was theoretical meaning that informants were purposefully and gradually selected based on emerging findings. Access to the informants was usually granted through snowball sampling, where initial participants are used to identify and connect the researchers with other theoretically relevant informants. The Alkalo (village head) was a starting point to gradually and purposefully select other people from the study villages, including recent malaria cases (individuals diagnosed by rapid diagnostic test (RDT) by a health worker) and their caretakers, compound heads, VHWs and marabouts (traditional healers). From the trial team, study nurses and fieldworkers were also included. Sampling aimed for maximum variation to ensure that all relevant groups in relation to the research question were included.

During the fieldwork, informal conversations were conducted with community members, trial nurses and fieldworkers. These conversations were useful to confirm or refute emerging findings and generate new hypotheses for testing.

Participants were identified using a bootstrap sampling technique with the population stratified by household and age (children (< 16 years) and adults). The sampling frame ensured that the number of households selected was in proportion to the size of the village. The questionnaire for children was administered to caregivers and where any of the initially selected persons were unavailable, the next person in the household in the same age category was approached to complete the questionnaire.

In-depth interviews (n = 88) and informal conversations (n = 5) were carried out with community members and field staff (Table 1).

In total, 741 questionnaires were completed; there were no refusals; 324 adults and 417 children (< 16 years) questionnaires were completed. The questionnaire for children (< 16 years) was administered to their caretakers (Table 2).

There were no local terms in the commonly spoken local languages, i.e. Mandinka, Fula and Wolof, corresponding directly to ‘asymptomatic disease’. Consequently, asymptomatic disease was explained as a health condition where a disease is present, but the affected person does not feel any signs and symptoms related to the disease. Based on this explanation, respondents interpreted the statement to mean a health condition where disease was present in the body but did not affect one’s appetite nor restricted their ability to carry out daily activities. The condition, to which everyone was considered susceptible, was understood as covering the following scenarios: (i) a minor illness which mild symptoms does not prevent people from carrying out daily activities; (ii) an illness that oscillates between symptomatic and asymptomatic phases; and, (iii) a condition where disease agents are present in the body but remain hidden until something triggers their manifestation in apparent symptoms. During the asymptomatic phase, the so-called ‘body soldiers’ (i.e. a representation of antibodies provided in health messages) are fighting the hidden disease but produce no apparent symptoms. Symptoms only appear when the body soldiers are defeated in the presence of external triggering factors. The elaborated local model of illness progression for asymptomatic conditions therefore presents the following characteristics: (i) everyone is susceptible to an asymptomatic condition; (ii) the disease can remain hidden for a variable period, depending on the fight in the body (body soldiers); (iii) symptoms will manifest when body soldiers are defeated or when certain triggers occur; (iv) disease can be transmitted even in asymptomatic form; and, (v) asymptomatic conditions should be treated when they become symptomatic.

Malaria was described as one of the conditions that could be asymptomatic. The majority of respondents (73%) thought that malaria can be hidden in the body without showing symptoms (Table 3). The proportions of those who thought so were similar across gender, ethnicity, educational level and socio-economic status. Respondents in the survey considered this form of hidden malaria most likely to be present in those living in the same household with a malaria case (71%), with no statistically significant differences across the socio-demographic characteristics (Table 3). Similarly, 78% of respondents stated that living in the same household as someone having malaria increased their personal risk of getting malaria. This varied by whether the respondent thought malaria could be asymptomatic, with 80% of those who thought malaria could be asymptomatic considering they were at increased risk as compared to 69% of those who did not (p = 0.002). 91% of respondents reported having a mosquito net in the home, and this did not vary by whether the respondent thought malaria could be asymptomatic or not (91%) and 88% of net use respectively (p = 0.168).

Qualitative interviews indicated that asymptomatic malaria was perceived to be hidden in different parts of the body and frequently in the head and joints where pain is first experienced.

“Generally, diseases can be housed in different parts of the body. Most times, for malaria the head is the problem and it starts with that place.” (Adult man, Farmer)

The time it takes for malaria symptoms to appear varied depending on a combination of factors such as: (i) one’s ability to withstand or cope with illness represented by the concept of ‘body strength’ and, (ii) the duration the body soldiers of the affected individual fights. For instance, the period of pregnancy was considered a phase of low body strength and thus pregnant women were perceived to have weaker body soldiers. Following these logics, the strength of the body (i.e. blood or body soldiers) can be increased or nourished by consuming certain foods such as green leafy vegetables and decreased through hard work and taking cold baths. This illustration reinforces the notion that one is asymptomatic when the body is strong and can thus hide the disease. When the body is weakened by the culmination of a set of external triggers (i.e. sun, milk, hard work), the symptoms of the disease can no longer be hidden and start to emerge. Most of the respondents (91%) thought that if malaria was hidden in the body, hot sun can make the symptoms appear. This perception significantly varied across ethnicity (Mandinka (95%), Wolof (91%) and Fula (83%), P < 0.001), and socio-economic levels (wealthiest quartile (89%), 2nd quartile (91%), 3rd quartile (97%) and poorest quartile (88%), p = 0.043) (Table 3). Among those who thought that if malaria was hidden in the body, 85% reported that drinking milk could make the symptoms appear, with similar proportions across socio-demographic characteristics.

It was widely acknowledged that mosquitoes could directly cause malaria (99.8%) and increased malaria risk was associated with mosquito density, which was related to stagnant water. Another commonly mentioned way of contracting malaria was ‘body heat’ transfer, understood as the transmission of heat (and disease) through direct (e.g. sleeping together with a malaria case) or indirect (e.g. sleeping in the place where a malaria case person was sleeping before) contact. In addition, the dormant state of malaria could be triggered to an active state by a mosquito bite (89%) (with similar proportions across the socio-demographic characteristics), resulting in apparent symptoms such as fever, headache, vomiting and body aches.

When malaria is related to and often even equated with the folk illness joontinoji (Fula), it is perceived to progress from its symptomatic phase to yellow fever (Chawnabee-Fula).

“When malaria has power, it can change into yellow fever” (Adult farmer, Talen Fula).

This progression was said to be more common during the rainy season. Yellow fever, locally referred to as Chawnabee (Fula), Sumuyaa (Tilibonka), Sai (Tilibonka) and Paices (Wollof), was believed to affect mostly children. The symptoms (yellowing of the eyes and vomit, fever, the changing colours of the palms of the hands) appear temporarily and then the disease hides again. The appearance of the symptoms is triggered by the consumption of specific food items, such as milk, which were more commonly available during the rainy season. During the symptomatic phase the disease can be transmitted to others by looking into the sick person’s eyes.

Although most people accepted that malaria could be asymptomatic, people do not actively seek treatment when symptoms are absent. People perceived analgesics (paracetamol or ibuprofen) taken after experiencing mild malaria symptoms to strengthen the body enough so it can hide the remaining malaria. Such hidden malaria is then considered undetectable by biomedical diagnostic tools, such as RDTs.

Informants generally considered it unnecessary to take medication without having any symptoms. However, when anti-malarial treatment is given after screening and the individual found to be positive, it was perceived to be a necessary means of disease prevention. This is consistent with local practices of self-protection with amulets or charms commonly referred to as fankanta (Mandinka) to prevent ailments such as jinn afflictions, common childhood illnesses or the ‘evil eye’ during women’s pregnancy. Once anti-malarial medication is consumed after screening, the medication is perceived to increase the body’s strength, enabling it to engage in a fight with the disease. In contrast to analgesics, malaria medication strengthens the body to the point where it can eliminate the disease rather than hide it. During this process, the blood becomes hot, making people sweat. Observed sweating after taking anti-malarial treatment was therefore seen as evidence of treatment efficacy.

“If you take anti-malarial treatment, it goes into the blood to fight what it is meant to fight. If you take the pills, it goes through the blood, which gets hot to fight the disease and when you sweat, then they say that you are feeling better from malaria and the medicine is good for you.” (Adult man, Farmer)

The efficacy of the anti-malarial medication was also perceived to be contingent on the prior ‘body strength’ of the individual. As a result, there was a general notion that individuals differed substantially and therefore that the treatment might work for some (eliminating the disease) and fail for others (hiding the disease only). The failure of treatment for some individuals was also attributed to the perceived strength of the anti-malarial medication in relation to its dosage. Especially taking an incomplete anti-malarial regimen could trigger the symptoms to reappear.