Malaria in children and women of childbearing age: prevalence and knowledge in the province of Nyanga, Gabon

Background: There is little information on the social perception of malaria and the use of in especially can help in reducing the burden of malaria among vulnerable groups, particularly pregnant women and children aged under 5 years old living in malaria endemic settings. This study was designed to assess the prevalence of malaria and the knowledge and attitude towards this disease in households in the Nyanga Province. Methods: A cross-sectional study was conducted to assess malaria knowledge, prevention practices and prevalence of the infection in five departments of the Nyanga Province. Malaria infection was confirmed using rapid diagnostic tests. A questionnaire was administered randomly to 535 households during a two weeks period in March 2018. Overall, the respondents’ socio-demographic characteristics, knowledge on malaria, malaria prevention practices and malaria prevalence were evaluated and compared across the five departments. Results: Data was collected on 1,307 participants were included in this study, 631 women of childbearing age (including 61 pregnant women) and 676 children. Practically the entire (97.7%) interviewed population had already heard about malaria and attributed the cause of malaria to a mosquito bite (95.7%). This survey revealed that the bed net coverage rate was 73.3%. The study observed an average malaria parasite prevalence of 13.9%. All departments of Nyanga province had significant level of malaria infection except for the Mayumba department where no plasmodial infection was found. The overall prevalence of the plasmodial infection was significantly higher in children and pregnant women compared to adults in the cities of Tchibanga and Moabi. Conclusion: Malaria is highly prevalent in the province of Nyanga. Our findings show that children under five and pregnant women are more vulnerable to malaria in this area of the country. This study reveals that respondents have a high knowledge of mode of transmission, malaria symptoms and preventive measures. Despite this high level of knowledge of the disease and its preventive measures, the incidence of malaria remains relatively high in this rural community highlighting the need for continuous strategic interventions particularly health awareness and educational programs

assess the prevalence of malaria and the knowledge and attitude towards this disease in households in the Nyanga Province. Methods: A cross-sectional study was conducted to assess malaria knowledge, prevention practices and prevalence of the infection in five departments of the Nyanga Province. Malaria infection was confirmed using rapid diagnostic tests. A questionnaire was administered randomly to 535 households during a two weeks period in March 2018. Overall, the respondents' socio-demographic characteristics, knowledge on malaria, malaria prevention practices and malaria prevalence were evaluated and compared across the five departments. Results: Data was collected on 1,307 participants were included in this study, 631 women of childbearing age (including In 2019, malaria remains the deadliest parasitic disease for human beings. In 2018, an estimated 228 million cases of malaria occurred worldwide, most of which were in the WHO African Region (200 million or 92%). The same year, 405,000 malaria-related deaths were recorded. Children under 5 years old are the most vulnerable group affected by malaria, in 2017 they accounted for 61% (266 000) of all malaria deaths worldwide [1]. It is now known that pregnant women are more susceptible to malaria than their non-pregnant peers [2]. Malaria during pregnancy is responsible for serious consequences for both the mother and her child, among which fetal growth restriction, prematurity and still birth contribute to perinatal and neonatal mortality [3]. In areas where the intensity of transmission is moderate to high, leading to higher levels of acquired immunity, most P. falciparum malaria infections during pregnancy remain asymptomatic and are frequently undiagnosed and untreated [4]. The 2018 malaria report also reveals insufficient levels of access and adhesion to lifesaving malaria tools and interventions. A considerable proportion of people at risk of infection are not being protected, including pregnant women and children in Africa [1].
Gabon is a hyperendemic area in which malaria burden fluctuates. Transmission is perennial since the equatorial climate favors mosquito proliferation and larval development.
However, over the last decade, Gabon has gradually strengthened malaria control interventions.
Changes in the national antimalarial policy such as the introduction of artemisinin-based combination therapy (ACT) as first-line treatment in all public facilities, the introduction of malaria rapid diagnostic tests (RDTs), the distribution of impregnated bed nets, and the implementation of intermittent preventive treatment during pregnancy have led to a decline in the malaria burden in urban areas [5].
After the implementation of artemisinin-based combination therapies (ACTs) in 2005, a decrease in malaria burden was observed, but for the past few years, a recrudescence is noted in the urban areas of Franceville and Libreville. However, prevalence did not change in rural areas [6].
Nyanga is the southernmost province among Gabon's nine provinces with a population of 52,854 inhabitants. The provincial capital is Tchibanga, which had a total of 31,789 inhabitants in 2013 (more than half of the total population in the province). Nyanga is the least populated province of the nine and the second least developed, following Ogooué-Ivindo. The Nyanga province has poor economic development, few industries are present and it is surrounded by forest and crossed by several rivers.
As malaria control interventions are increased, rational approaches are needed to monitor their impact over time. However, the prevalence of malaria has not been well described in the rural Nyanga province as very little data on the epidemiology of malaria is available. Furthermore little efforts have been placed on examining the inhabitants' knowledge regarding malaria transmission modes and the preventive methods used and practiced among people living in rural communities, particularly in the Nyanga province.
To truly fight malaria in the world, a comprehensive approach that includes vector control measures and early diagnosis and treatment, especially at the village level, is needed. Using this approach, the American NGO Medical Care Development International (MCDI) has been able to significantly reduce the burden of malaria in Equatorial Guinea in recent years [7] .
This study piloted an active screening approach to monitor malaria prevalence in two target populations: women of childbearing age (including pregnant women) and children under five years old. Additionally, their knowledge on malaria and the conducts of these women regarding the disease in the Nyanga Province were evaluated.

Population and study sites
This community-based cross-sectional descriptive and analytical epidemiological study was conducted from March 18th to 27th 2018 in five administrative centers of the Nyanga province, located in southern Gabon, to assess the population's basic knowledge on malaria and their behavior regarding prevention, as well as malaria prevalence. The cities included in this study were: Mayumba, Moabi, Mabanda, Moulengui-Binza and Tchibanga, respectively, in the departments of Basse-Banio, Douigny, Doutsila, Mongo and Mougoutsi (Fig. 1).
The studied population in this study was composed of children under 5 and women of childbearing age. Inclusion criteria set for sampling eligible participants stipulated that participants must:1) reside within the study site during the study period; 2)have signed the consent form; 3) be aged 5 years old or under for children and aged 15 to 49 years old for women of childbearing age. The study was approved by the Gabonese National Ethics Committee (N° 001/PR/SG/CNE/2018).
Sampling and collection of data on preventive measures against malaria and level of knowledge of participants

Malaria parasite detection and treatment
After obtaining the consent of all recruited participants, a rapid diagnostic test was performed.
Capillary blood was obtained via finger stick for malaria testing using RDT (Malaria Ag P.f/Pan, SD Bioline®). Test results were recorded on a patient sheet and data on symptoms were also collected. Knowledge and action for malaria prevention and vector control were also evaluated. The majority of the women thought that the use of bed nets at home and environmental remediation (95.06% and 84.57%, respectively) could prevent malaria. More than half of the respondents thought that spraying insecticides could also prevent malaria (64.7%). Less than half of the respondents thought that vaccination and washing their hands before eating (64.5% and 49.9%, respectively) could also be ways to prevent malaria.

Information source
The interviewed people who had already heard of malaria reported receiving information on malaria from one or more sources. The sources of information were varied and are reported on Table 2.
Among the different sources of information, the largest proportion of respondents had received information regarding malaria from a media source (67.7%), followed by hospitals, health center or doctors (22.9%). The sources least reported were schools and sensitization campaigns (2.6%). Among media sources social television and social media were a major source of malaria information for all respondents.

Preventive measures
This survey revealed that the bed-net coverage rate was 73.3% (924/1260). Insecticide spraying was used by 52.1% (574/1103) of the subjects. To prevent mosquitos in the home, the use of fans was the most commonly used method in this study (58.4%), while air conditioners were only used by 3.2% (p < 0.05) of participants. More than half of the women had not received an Insecticide-Treated bed Nets (ITN) during antenatal visits of their last pregnancy. Sixty-six percent (66.1%) of women said that Long Lasting Insecticide Nets (LLIN) is free in public health facilities, but 26.1% reported that it was not free. As for intermittent preventive treatment with Sulfadoxine-Pyrimethamine (IPT-SP), 50.2% of women said that IPT-SP is free in public health facilities, whereas 32.6% of them stated it was not.

Characteristics of plasmodial infection
The study observed an average malaria parasite prevalence of 13 11.4% (57/501) in adults (women of childbearing age), and 20.0% (12/60) in pregnant women (p = 0.01). It was significantly different between categories (children, adults, and pregnant women) in the cities of Tchibanga (p = 0.002) and Moabi (p = 0.006). The general characterization of plasmodial infection by departmental capitals is summarized on Table 3. There was no significant difference in the prevalence between age groups in children under 5 years. In addition, the prevalence of infection was significantly different between age groups in women of childbearing age. Women between 11 to 20 years of age (37.50%) were more infected than other women in other age groups (p = 0.012) as shown in Fig. 3. The there was no significant difference between the number of infected individuals sleeping under mosquito nets and using insecticides and the ones that are uninfected and do not sleep on a net and do not use insecticides (p > 0.05) as shown in Fig. 2.

Discussion
This study provides the first baseline data on the epidemiological parameters, characteristics of plasmodial infection, and the knowledge and prevention practices regarding malaria residents in a vulnerable population of the Nyanga province in Gabon.
In this cross-sectional survey, 1,307 individuals composed of women of childbearing age and children under 5 years old were included.
This unprecedented study provides baseline data on epidemiological parameters, characteristics of plasmodial infection, and the knowledge and prevention practices regarding malaria residents in a vulnerable population of Nyanga Province in Gabon.
The vast majority of respondents (97.7%) in Nyanga province (rural area) was aware of malaria.
In our study, we showed that our study population had adequate knowledge regarding the mosquito bite as the means of transmission. Our results also demonstrate that fever, and headache, fatigue and aches were correctly identified as symptoms of malaria which corroborates results from similar studies conducted in Cameroon, Ethiopia and Tanzania [8,9,12] where respondents were able to name at least one symptom of malaria. National malaria programs need to know how and where their populations obtain information regarding malaria in order to better plan their communication activities. Our study revealed that most of the population obtains information on malaria from media source and, to a lesser extent, from hospitals and health centers. Given the young mean age of the interviewed women (334.05 ± 129.54 months), these results are to be expected as, in Gabon, the majority of young people watch television and are connected to social media via the internet. These findings are different from those obtained in another study led in India [13] in which overall, hospitals, health centers or doctors were the most frequently cited interpersonal source of information about malaria. This disparity could be explained by the difference in age of the women included in the different studies. These results also highlight the need for public health professionals to work together with media, as well as hospital facilities and doctors, to disseminate accurate and reliable malaria information and use age-appropriate means of communication in order to have the most impact.
Respondents showed adequate knowledge in regards to bed nets, spraying of insecticides and environmental sanitation as effective prevention strategies. Over 95% of people interviewed in Nyanga Province reported using bed nets to prevent malaria. Indeed, in Gabon and in other countries of Central Africa, the national policy strategies against malaria relies on the use of Insecticide-treated bed nets. During this last decade, a concerted campaign against malaria has led to unprecedented levels of interventions across sub-Saharan Africa [14]. African governments and decision-makers in the health sector are in the habit of conducting mass awareness campaign promotion through audiovisual networks, social networks and newspapers. School age children usually are educated about malaria in school. Although these campaigns take place throughout the year, they are more emphasized during the internationally celebrated malaria awareness day. Also in Gabon, as other Malaria endemic countries, insecticide-treated bed nets are freely distributed to pregnant women and children under 5 years, as is intermittent preventive treatment for pregnant women, Indoor residual spraying is also now being widely used across Africa with increasing amounts of coverage achieved [5,15]. Our results on measures of prevention are similar to those obtained in a recent study led in Cameroon and in Gabon [11,16].. In our study, some respondents believed that Malaria infection was caused by getting wet in the rain. These findings are not surprising as it has been shown in another of our study that some people associate fever from getting wet in the rain with malaria (data not published).
Our study showed a malaria infection lower (13.6%) than in other rural area (Makokou 53.6%, Lastoursville 79.5%, Oyem 44.2%) [6,17]. In these studies, the tested study population was in based in hospitals while our study tested the general population providing an explanation for the low prevalence of malaria infection in the present study. Our low prevalence of malaria infection could also be associated with the high level of knowledge of preventive measures in our study area. [18].
The distribution of the malaria prevalence among the five departments of the Nyanga province was quite varied. The departments of Tchibanga and Moabi had a prevalence of 18.7% and 14.8% respectively, the highest prevalence for malaria parasite. The departments of Moulengui-Binza and Mabanda both showed parasite prevalence lower than 10% while in the department of Mayumba, malaria parasite was not at all detected. This variation between departments could be explained by some factors such as the population density. In fact, Tchibanga main town of the Nyanga province which comprises of more than half of the total population in that geographical area. It was surprising that none of 188 participants that were tested in Mayumba were positive for malaria infection since Gabon is hyperendemic for malaria.
The overall prevalence of the plasmodial infection was significantly higher in children and pregnant women compared to adults in the cities of Tchibanga and Moabi. It has been reported that prevalence was more common for school-aged children compared to other groups, including under-fives who, together with pregnant women, are still considered to be at highest risk of malaria[1] The protective efficacy of ITNs is defined as the proportion of human exposure to malaria vectors prevented by ITN use out of total exposure i.e. compared to a non-user [19]. In our study, the prevalence of infected individuals sleeping under mosquito nets and using insecticides was similar to that of uninfected persons who do not sleep on a net and do not use insecticides. The similar proportions of Plasmodium-infected individuals, sleeping under mosquito nets and non-infected individuals with non-mosquito-borne plasmodia may indicate that Plasmodium infection is more likely to occur during waking hours than during sleep hours.

Conclusion
Malaria is highly prevalent in the province of Nyanga in Gabon. Our findings show that children under five and pregnant women are more vulnerable to malaria in this area of the country. This study reveals that respondents have a high knowledge of mode of transmission, malaria symptoms and preventive measures for the disease. Despite this high level of knowledge of the disease and its preventive measures, the incidence of malaria remains relatively high in this rural community highlighting the need for continuous strategic interventions particularly health awareness and educational programs.  Comparison between infected and uninfected women of childbearing age. Comparison of preventive measures between infected and uninfected individuals.