Socio-demographic trends in malaria knowledge and implications for behaviour change interventions in Zanzibar.

BACKGROUND: Zanzibar is among the few places within East Africa that have documented a significant reduction of malaria morbidity and mortality. Despite tremendous gains over the past decade, malaria transmission still persists in Zanzibar. This study aimed at understanding levels of malaria knowledge to provide recommendations that can be used to reinforce and scale up targeted malaria social and behaviour change interventions. METHODS: A descriptive cross-sectional survey was conducted through an administered questionnaire to 431 households selected randomly. The interviewees were the heads of household or representative adults above 18 years. This study investigated the levels of knowledge about the causes, symptoms, and prevention of malaria in areas with high (> 1.9 per 1000) and low (< 1 per 1000) incidence of local malaria cases. The Principal Component Analysis (PCA) was used to compute the composite variable of each category. Descriptive statistics were calculated to understand variables of interest between low and high transmission areas. Multinomial logistic regression model was used to compare knowledge on malaria based on key variables. RESULTS: A total of 431 heads of households were interviewed. Respondent age, education level, and wealth status were significantly associated with variations in level of malaria knowledge. Old age was found to be significantly associated with low knowledge of malaria (P < 0.001). The majority of study participants who had secondary and higher education levels had good knowledge of malaria (P < 0.006). Participants characterized as middle-income had good knowledge compared to those characterized as low-income (P < 0.001). CONCLUSION: The study identified existing gaps in malaria knowledge in low and high transmission areas. Low levels of malaria knowledge were documented among elderly and populations with lower education and income levels. There is a need to extend mobilization, advocacy, and expand channels of communication to reach all community members. The reported gaps in knowledge are important to consider when designing strategies to engage communities in malaria elimination in Zanzibar. Tailored social and behavioural change interventions aiming to increase malaria knowledge could enhance the uptake of malaria prevention services in the community.

Stakeholder perspectives on a door-to-door intervention to increase community engagement for malaria elimination in Zanzibar.

BACKGROUND: Malaria remains a major public health problem in sub-Saharan Africa. The 2021 World Health Organization (WHO) World Malaria Report indicates a slowing in the decline of malaria incidence since 2015. Malaria prevalence in Zanzibar has been maintained at less than 1% since 2010, however from 2018 to 2021, the annual number of reported malaria cases has gradually increased from 4106 to 9290. Community engagement has been emphasized by the WHO for reducing malaria transmission. To better understand the potential for a door-to-door approach for malaria, a three-month pilot programme was carried out. This qualitative study aimed at understanding stakeholder experiences with the pilot programme and considerations for its implementation. METHODS: Through multistage sampling, four shehias (wards-the lowest administrative structure) with comparatively high (> 1.9 per 1000) and four with low (< 1 per 1000) incidence of local malaria cases were selected and involved in a door-to-door pilot intervention. The qualitative study was conducted after the pilot intervention and employed focus group discussions and in-depth interviews. All field notes were written on paper and audiotaped using digital audio-recorders. Summaries were developed by integrating field notes with reviews of recordings; themes were developed based on the topics identified a priori. Responses for each theme were summarized using an iterative process. RESULTS: Most community members reported high levels of acceptance of door-to-door interventions. Some factors that might affect implementation of door-to-door include, low risk perception of the disease, local beliefs and practice, lack of initiative from the programme level to involve communities, and political instability during the election period. All Community Health Volunteers (CHVs) recommended this approach for community engagement, however, ensuring adequate resources was identified as a key factor for ensuring its sustainability. CONCLUSION: The door-to-door intervention was perceived as helpful for promoting community engagement. There are several factors to consider including ensuring that CHVs are provided with adequate education, regular supervision, and have access to essential resources. Community leaders should be fully involved in choosing CHVs that are acceptable to the community. To ensure sustainability, the government should allocate sufficient resources and improve coordination systems.

Acceptability of single screening and treatment policy for the control of malaria in pregnancy: perceptions of providers and pregnant women from selected health facilities in Lindi region, Tanzania.

BACKGROUND: Tanzania started implementing single screening and treatment (SST) for all pregnant women attending their first antenatal care (ANC) visits in 2014, using malaria rapid diagnostic tests (RDTs) and treating those who test positive according to the national guidelines. However, there is a paucity of data to show the acceptability of SST to both pregnant women and health care workers (HCWs), taking into consideration the shortage of workers and the added burden of this policy to the health system. This study assessed the perceptions and opinions of health service users and providers to determine the acceptability of SST policy. METHODS: Pregnant women and HCWs in eight health facilities in two districts of Lindi region (Kilwa and Lindi) were interviewed using semi-structured questionnaires with open and close-ended questions. Both qualitative and quantitative data were collected, including demographic characteristics, women's experience, their perception on SST and challenges they face when receiving services for malaria offered at ANC. Experience of HCWs regarding the implementation of SST as part of routine services and the challenges encountered when providing ANC services for malaria in pregnancy (MIP) were also assessed. RESULTS: Of the 143 pregnant women interviewed, 97% viewed testing favourably and would wish to be tested for malaria again, while 95% were satisfied with services and reasons for testing during the first ANC visit. Nearly all (99%) would recommend their fellow pregnant women to be tested for malaria and all women recommended that the Ministry of Health should continue the SST strategy. This was despite the fact that 76% of the women experienced pain and 16% had anxiety as a result of finger prick. Sixteen HCWs (mostly nurses) were interviewed; they also viewed SST implementation favourably and reported feeling empowered to use RDTs for malaria screening. The main challenge identified by HCWs was that nurses are not allowed to prescribe anti-malarials to women who test positive and need to refer them to the outpatient department for treatment. CONCLUSION: SST was considered an acceptable approach to control MIP by HCWs and pregnant women, and they recommended the continuation of the policy. In addition, consideration should be given to implementing a task-shifting policy to allow nurses to dispense anti-malarials to pregnant women.

Evaluation of a single screen and treat strategy to detect asymptomatic malaria among pregnant women from selected health facilities in Lindi region, Tanzania.

BACKGROUND: In areas of high transmission, malaria in pregnancy (MiP) primarily causes asymptomatic infections; these infections nonetheless increase the risk of adverse maternal and fetal outcomes. In 2014, Tanzania initiated a single screening and treatment (SST) strategy for all pregnant women at their first antenatal care (ANC) visit using malaria rapid diagnostic tests (RDT) for surveillance purposes. However, there is paucity of data on the effectiveness of SST in the prevention of MiP. The objective of this study was to estimate the number of asymptomatic infections among pregnant women detected by SST, which would have been missed in the absence of the policy. METHODS: Data from pregnant women attending their first ANC visits between October 2017 and June 2018, including gestational age, history of fever, and RDT results, were abstracted from ANC registers in eight health centres in two randomly selected districts, Kilwa and Lindi, in Lindi Region. The proportion of symptomatic (with history of fever in the past 48 h) and asymptomatic pregnant women with positive RDTs were calculated and stratified by trimester (first, second and third). The study areas were categorized as low transmission with prevalence < 10% or moderate/high with ≥ 10%. RESULTS: Over the study period, 1,845 women attended their first ANC visits; 22.1% were in the first trimester (< 12 weeks gestation age). Overall 15.0% of the women had positive RDTs, and there was a trend towards higher malaria prevalence in the first (15.9%) and second (15.2%) trimesters, compared to the third (7.1%), although the differences were not statistically significant (p = 0.07). In total, 6.9% of women reported fever within the past 48 h and, of these, 96.1% were RDT positive. For every 100 pregnant women in the moderate/high and low transmission areas, SST identified 60 and 26 pregnant women, respectively, with asymptomatic infections that would have otherwise been missed. Among the 15.9% of women detected in the first trimester, 50.7% were asymptomatic. CONCLUSION: In areas of moderate/high transmission, many infected women were asymptomatic, and would have been missed in the absence of SST. The benefits on maternal and fetal birth outcomes of identifying these infections depend heavily on the protection afforded by treatment, which is likely to be greatest for women presenting in the first trimester when intermittent preventive treatment (IPTp) with sulfadoxine-pyrimethamine (SP) is contraindicated, and in areas with high SP resistance, such as most parts of Tanzania. An evaluation of the impact and cost-effectiveness of SST across different transmission strata is warranted.

Occurrence of Fungi and Mycotoxins in Fish Feeds and Their Impact on Fish Health.

The rapid population growth in developing countries has led to strong pressure on capture fisheries. However, capture fisheries have reached their maximal limits of fish production and are supplemented by farmed fish. The growth in aquaculture has led to high demand for fish feeds, which play a very important role in fish nutrition and health. Use of animal protein in fish feeds is expensive; hence, a majority of farmers from developing countries use local feed ingredients from plant origin as a source of dietary protein. However, these ingredients of plant origin provide the best natural substrates for fungi, which can be easily accompanied by mycotoxin development under suitable conditions. The locally made feed comprises ingredients such as soybeans, cottonseed cake, and wheat and maize bran which are mixed together and ground after which the compounded feed is pelleted and stored. Among the ingredients, maize and oilseeds are more susceptible for mycotoxigenic fungi compared to other ingredients. The outcomes of mycotoxin contamination in fish feeds are not different from other animal species intended for human consumption, and they are directly associated with production losses, particularly decreased weight gain and feed conversion, impaired immune system and reproductive performance, and increased fish mortality. Fish may also carry mycotoxin residues along the food chain, thus compromising human health. Hence, it is important to ensure the control of mycotoxin contamination in fish feeds, especially during the production and storage.

Effects of aflatoxin B1 on reproductive performance of farmed Nile tilapia.

This study evaluated the effect of dietary aflatoxin B1 (AFB1) on growth, milt and egg quality in matured Nile tilapia (Oreochromis niloticus). Triplicate groups of Nile tilapia (initial body weight 24.1 ± 2.6 g) were fed with either of four diets (Diets 1 to 4) designed to contain 0, 20, 200 and 2000 µg AFB1 kg-1 diets for 24 weeks. After 24 weeks of AFB1 exposure, growth was significantly (P <0.05) different between the control and the AFB1 exposed treatments in both sexes. No significant differences were observed in 17ß-oestradiol, absolute fecundity, oocytes volume and diameters between AFB1 exposure groups and the control group. However, we observed a significant reduction in relative fecundity and gonad somatic index (GSI) in females fed 2000 µg AFB1 kg-1 diet. On the other hand, we observed significant differences (P <0.05) in gonadosomatic index (GSI), testosterone, milt count and motility between males in the control group and AFB1 treatments. We conclude that rearing Nile tilapia with aflatoxin-contaminated diets for a prolonged period affects milt quality, fecundity (at higher doses) and growth performance. This implies that for optimal seed production, provision of aflatoxin free diets should be part of the management practices in Nile tilapia hatcheries.

Estimating malaria burden among pregnant women using data from antenatal care centres in Tanzania: a population-based study.

BACKGROUND: More timely estimates of malaria prevalence are needed to inform optimal control strategies and measure progress. Since 2014, Tanzania has implemented nationwide malaria screening for all pregnant women within the antenatal care system. We aimed to compare malaria test results during antenatal care to two population-based prevalence surveys in Tanzanian children aged 6-59 months to examine their potential in measuring malaria trends and progress towards elimination. METHODS: Malaria test results from pregnant women screened at their first antenatal care visits at health-care facilities (private and public) in all 184 districts of Tanzania between Jan 1, 2014, and Dec 31, 2017, were collected from the Health Management Information Systems and District Health Information System 2. We excluded facilities with no recorded antenatal care attendees during the time period. We standardised results to account for testing uptake and weighted them by the timing of two population-based surveys of childhood malaria prevalence done in 2015-16 (Demographic and Health Survey) and 2017 (Malaria Indicator Survey). We assessed regional-level correlation using Spearman's coefficient and assessed the consistency of monthly district-level prevalence ranking using Kendall's correlation coefficient. FINDINGS: Correlation between malaria prevalence at antenatal care and among children younger than 5 years was high (r≥0·83 for both surveys), although declines in prevalence at antenatal care were generally smaller than among children. Consistent heterogeneity (p<0·05) in antenatal care prevalence at the district level was evident in all but one region (Kilimanjaro). Data from antenatal care showed declining prevalence in three regions (Arusha, Kilimanjaro, and Manyara) where surveys estimated zero prevalence. INTERPRETATION: Routine antenatal care-based screening can be used to assess heterogeneity in transmission at finer resolution than population-based surveys, and provides sample sizes powered to detect changes, notably in areas of low transmission where surveys lack power. Declines in prevalence at antenatal care might lag behind those among children, highlighting the value of monitoring burden and continuing prevention efforts among pregnant women as transmission declines. The pregnancy-specific benefits and cost-effectiveness of antenatal care-based screening remain to be assessed. FUNDING: None.

Sex-Related Differences in Hematological Parameters and Organosomatic Indices of Oreochromis niloticus Exposed to Aflatoxin B1 Diet.

A 24-week feeding experiment was conducted to assess whether males and females of Oreochromis niloticus exhibit differences in their hematological responses and organosomatic indices to dietary AFB1 contamination. Triplicate groups of O. niloticus (initial body weight: 24.1 ± 0.6 g) were fed with four diets (Diets 1 to 4) containing 0, 20, 200, and 2,000 µg AFB1 kg-1. A significant decrease (P < 0.05) in hemoglobin (Hb), red blood cells (RBC), and hematocrit (Hct) was observed in AFB1 exposure groups, with the lowest levels recorded in the 2000 µg AFB1 kg-1 treatment. A significant increase in mean white blood cells (WBC), neutrophils, and lymphocytes was observed in AFB1 exposure groups. No sex-related differences in RBC, WBC, lymphocytes, monocytes, and neutrophils levels were observed. However, hemoglobin and hematocrit values for female O. niloticus were significantly lower than those for male O. niloticus. Organosomatic indices showed that the relative liver, kidney, and spleen weights were significantly higher (P < 0.05) in the AFB1 supplemented group than in the control group. However, the effect of aflatoxin on organosomatic indices does not depend on sex but rather depends on the dose of aflatoxin in the diet. These results provide useful information for monitoring changes in the health status of male and female O. niloticus.

Spatial variability in the density, distribution and vectorial capacity of anopheline species in Rufiji district, south-eastern Tanzania.

Malaria transmission varies from one area to another and there are also local difference in time and space. The objective of the study was to determine the local variability of entomological parameters namely, mosquito abundance, human biting rate (HBR), sporozoite rate for Plasmodiumfalciparum and entomological inoculation rate (EIR). The study was carried out in Rufiji District south eastern Tanzania from October 2001 and September 2004. Adult mosquitoes were collected indoors by CDC light traps. PCR was employed to identify the species within the Anopheles gambiae complex. ELISA was used to determine the sporozoite rate. Over a three year sampling period a total of 64,875 female mosquitoes were caught using light-traps, and of these 28% were Anopheles gambiae complex, 25% An. funestus Giles, 1% An. pharoensis Theobald, 46% Culex species and the rest were Mansonia uniformis Theobald. Mosquito abundance and species composition varied seasonally, spatially and between years. Using PCR, three members of the Anopheles gambiae complex namely An. gambiae s.s. Giles (69%), An. arabiensis Paton (23%) and An. merus D6nitz (7%) were confirmed to occur in the study area. Plasmodiumfalciparum circumsporozoite antigen (CSA) rates were 3.5% for An. gambiae complex and 2.3% for An. funestus. The mean EIR ranged from 28-275 infective bites/person/year. Transmission indices varied over short distances, seasonally and between years. In conclusion, malaria transmission indices in the study area are one of the highest in Tanzania; and there is high variability of entomological parameters over a small geographical area.