5202

DISTRIBUTION OF ANOPHELES MOSQUITOES AND THEIR ROLE IN MALARIA TRANSMISSION IN SOUTHWESTERN ETHIOPIA

Nigatu Eligo1, Teklu Wegayehu1, Myrthe Pareyn2, Girum Tamiru1, Bernt Lindtjørn3, Fekadu Massebo1

1Arba Minch University, Arba Minch, Ethiopia, 2Institute of Tropical Medicine, Antwerp, Belgium, 3University of Bergen, Bergen, Norway

The species distribution of malaria mosquitoes and their role in disease transmission varies from place to place. Hence, updating the species distribution and identifying their role is essential to design appropriate interventions. This study aimed to assess the Anopheles mosquito species and their infection rate in Southwest Ethiopia. A cross-sectional multistage sampling technique of adult malaria mosquitoes was done from June 2018 to July 2019. With a purposeful selection process, four malaria-endemic zones in the region, two malaria-endemic districts in each zone, and two malarious villages in each district were chosen. Ten per cent of households in each village were visited once to collect adult mosquitoes using Center for Disease Control and Prevention (CDC) light traps. The head and thorax of adult Anopheles mosquitoes were evaluated for circum-sporozoite proteins (CSPs). At the same time, legs and wings were used to identify sibling species using a polymerase chain reaction (PCR). A total of 1445 Anopheles mosquitoes were examined, comprising eight species, An. arabiensis (84.9%), An. parensis (9.1%), An. pharoensis (4.8%), An. pretoriensis (0.6%), An. demeilloni (0.2%), An. kingi (0.1%), An. sergentii (0.1%), and An. tenebrosus (0.1%). Of 813 An. gambiae complex evaluated by PCR, 97% (785/813) were An. arabiensis and 3% (28/1445) were not amplified. There were 133 An. funestus complex tested for speciation, 88% (117/133) were positive for An. parensis, and 11% (15/133), were not amplified. A single specimen (1%) amplified for An. funestus complex primers was not among the complex species and was later confirmed as An. sergentii by DNA sequencing. Among the 1399 Anopheles tested for CSPs by ELISA, Plasmodium falciparum CSP rate was 0.4% (95% CI: 0.1- 0.8), and it was 0.1% (95% CI: 0.002-0.4) for P. vivax. An. arabiensis and An. pharoensis were widely distributed species in the region, but only An. arabiensis was found to be positive for CSPs. Anopheles arabiensis is the primary vector of malaria in the region.

5369

MALARIA MISDIAGNOSIS IN THE ROUTINE HEALTH SYSTEM IN ARBA MINCH AREA DISTRICT IN SOUTHWEST ETHIOPIA: AN IMPLICATION FOR MALARIA CONTROL AND ELIMINATION

Engida Yigezu1, Biniam Wondale1, Daniel Abebe2, Girum Tamiru1, Nigatu Eligo1, Bernt Lindtjørn3, Endalamaw Gadisa2, Fitsum Girma Tadesse2, Fekadu Massebo1
1Arba Minch University, Arba Minch, Ethiopia, 2Armauer Hansen Research Institute, Addis Ababa, Ethiopia, 3Centre for International Health, University of Bergen, Bergen, Norway

Accurate diagnosis of malaria is vital for the appropriate treatment of cases and to interrupt its transmission. The objective of this study was to compare microscopy with nested polymerase chain reaction (PCR) to diagnose malaria infections. A cross-sectional survey on health facilities was conducted from November 2019 to January 2020. Two hundred fifty-four microscopically negative and 193 microscopically positive malaria cases were assessed. Of the 193 malaria-positive patients, 46.1% (95% confidence interval (CI): 38.9-53.4) (89/193) were Plasmodium falciparum infections, 52.3% (95% CI: 45.0-59.5) (101/193) were P. vivax infection, and 1.6% (3/193) had mixed infection of P. falciparum and P. vivax. Of the microscopically positive cases of P. falciparum, 84.3% (75/89) were confirmed as P. falciparum, 3.4% (3/89) were P. vivax and 11.2% (10/89) were mixed infections with P. falciparum and P. vivax, and only one case was negative molecularly. Similarly, of the microscopically positive cases of P. vivax cases, 92.1% (93/101) were confirmed as P. vivax, 5.9% (6/101) were P. falciparum and 1% (1/101) was a mixed infection. A single case was negative by molecular technique. Of the 254 microscopically negative cases, 0.8% of patients tested positive for P. falciparum and 2% for P. vivax. Using PCR a reference, the sensitivity of microscopy for detecting P. falciparum was 89%, and for P. vivax, it was 91%. The specificity of microscopy for detecting P. falciparum was 96%, and for P. vivax, it was 98%. However, the sensitivity in detecting mixed infection of P. falciparum and P. vivax was low (8%). Thus, many P. falciparum and P. vivax mixed infections were microscopically overlooked and underreported. In addition, there were cases left untreated or inappropriately treated. Therefore, the gaps in the microscopic-based malaria diagnosis should be identified and regularly monitored to ensure the accuracy of the diagnosis.

6182

LARGER FAMILIES ARE LESS LIKELY TO ACHIEVE UNIVERSAL LONG-LASTING INSECTICIDAL NETS COVERAGE IN ETHIOPIA

Misganu Endriyas Tantu1, Tarekegn Solomon1, Taye Gari1, Teka Samuel1, Bernt Lindtjørn2

1Hawassa University, Hawassa, Ethiopia, 2Centre for International Health, University of Bergen, Bergen, Norway

In a population with a high risk of malaria infection, using long-lasting insecticidal nets (LLIN) is an essential malaria prevention method. Ethiopia has been distributing LLIN for free. However, ensuring sufficient access and use of LLINs requires close monitoring and evaluation. Hence, this study assessed ownership of LLINs in the Sidama Region in Southern Ethiopia. A community-based cross-sectional study was conducted in February and March 2023. Multi-stage cluster sampling was used to select representative households. We estimated LLIN coverage in terms of WHO’s universal LLIN coverage (at least one LLIN for every two people) and national LLIN targets, which aim at 100% LLIN coverage of the population at risk with one LLIN per sleeping space. In addition, the LLIN distribution depends on the family size, with one LLIN for a family size of 1-2, two LLINs for a family size of 3-5, three for 6-7 and four for eight or more family members. We did not assess the quality of the LLIN. A total of 1647 households were included in the study. Most households were led by males (89%), farmers (63%) and persons who were unable to read and write (55%). The ownership of at least one LLIN per household was 85% (95% CI 83.5 – 86.9%; 1405 of 1647 households). About two-thirds (66%) of households had at least one LLIN for every sleeping space, and about half (49%) had the required LLIN per family size. Only 36% of households had universal access to LLIN. Moreover, only 33% of households with children less than under-five years of age or pregnant women had universal access to LLIN. Homes with larger families (Adjusted Odds Ratio (AOR): 8.14 [6.26, 10.58]) and female-headed households (AOR: 3.08 [1.47, 6.43]) were more likely to have unmet universal LLINs coverage. We conclude that the LLIN coverage was low compared to WHO-recommended universal LLIN coverage and national LLIN targets per sleeping space and family size. The National LLINs distribution standard should consider additional LLIN for larger families.

184

UTILIZATION OF LONG-LASTING INSECTICIDAL NETS AT HOUSEHOLD AND INDIVIDUAL LEVELS IN SIDAMA REGION, SOUTHERN ETHIOPIA

Teka Samuel Debeko1, Tarekegn Solomon Shanka1, Taye Gari Ayana1, Misganu Endriyas Tantu1, Bernt Lindtjørn2

1Hawassa University, Hawassa, Ethiopia, 2Centre for International Health, University of Bergen, Bergen, Norway

Malaria is an increasing public health problem in Ethiopia, sometimes occurring as epidemics. The utilization of long-lasting insecticidal nets (LLIN) is an essential malaria prevention tool, and there is limited information on its utilization in the Sidama Region in Southern Ethiopia. This study aims to assess LLIN use in rural Sidama. Using multi-stage cluster sampling, a cross-sectional study was conducted in two districts in February and March 2023, including 1,647 households with 8,054 individuals. LLIN utilization was measured by the self-report of sleeping under LLINs the day preceding the survey and was estimated at household and individual levels. Descriptive statistics and binary logistic regression were performed. The mean age of house members was 23 years; half of the participants were males, and 47% could not read and write. Of 1647 households, 85% (95% CI 83 – 87%) owned at least one LLIN, from which 78% (95% CI 76 – 80%) used at least one LLIN the preceding night. However, the individual-level LLIN use showed that only 31% slept under a bed net the previous day. Females (Adjusted Odds Ratio (AOR): 1.5 (1.4, 1.7)) and members from large families (AOR: 1.3; 95% CI 1.1, 1.4) were more likely not to sleep under LLIN. Meanwhile, literate household members (AOR 1.2; 95% CI 1.1, 1.4) were likelier to sleep under bed nets than those who couldn’t read and write. Our study shows that the proportion of the population in a malaria- endemic area who slept under LLIN the previous night was far below what is required to control malaria. Furthermore, our study shows that measuring individual LLIN use may give more appropriate information for control than using the household as a unit, as often recommended.

6502

EFFECT OF CHLOROQUINE ON PLASMODIUM VIVAX PARASITE TRANSMISSION TO MOSQUITOES IN THE EARLY POST-TREATMENT HOURS, ARBA MINCH, ETHIOPIA

Girum Datanbo1, Biniam Wondale1, Nigatu Eligo1, Endalamaw Gadisa2, Bernt Lindtjørn3, Fitsum Girma2, Fekadu Massebo1

1Arba Minch University, Arba Minch, Ethiopia, 2Armauer Hansen Research Institute, Addis Ababa, Ethiopia, 3Centre for International Health, University of Bergen, Norway

Ethiopian malaria guidelines prescribe chloroquine (CQ) for Plasmodium vivax. Data on human-mosquito malarial parasite transmission in the initial days following CQ therapy is scarce. This study examines CQ’s early transmission-blocking impact. Thirty microscopically confirmed P. vivax patients in Arba Minch, Ethiopia, participated in an open-label experimental follow-up investigation. Participants were treated with CQ for three days and observed for 42 days. Clinical, microscopic blood film and quantitative polymerase chain reaction (qPCR) tests were performed. Anopheles arabiensis colony mosquitoes were tested using artificial membrane feeding. While nested polymerase chain reaction (nPCR) was used to measure the clearance of asexual parasites, qPCR was used to measure the clearance of mature gametocytes. 67% (20/30) were positive for P. vivax alone, 7% (2/30) for both P. vivax and P. falciparum, and 10% (3/30) were positive for P. falciparum by nPCR. Plasmodium vivax mono-infection cases confirmed by nPCR were included in the analysis. 85% (17/20) of confirmed cases were infectious to mosquitoes before treatment and 59% (10/17) after 8 and 24 hours of treatment. The median oocyst infection rate dropped from 51% (245/480 mosquitoes) (ranges: 14-83%) at baseline to 36% (209/522 mosquitoes) after 8 hours and 17% (81/440 mosquitoes) at 24 hours post-treatment. The circumsporozoite protein rate of An. arabiensis was 3% (95% CI: 1-7) before treatment, 3% (CI: 1-5) at 8 hours post-treatment, and 0.7% (CI: 0.1-2.5) at 24 hours post-treatment. Eight hours post-treatment, all patients had gametocytes and sexual parasites. After 24 hours of treatment, positive cases dropped to 50%, but mosquitoes continued to transmit parasites. On day three post-treatment, 19 of 20 patients obtained gametocyte clearance and all patients showed complete asexual parasite clearance. This finding implies that the P. vivax-positive cases continue supporting parasite transmission for at least 24 hours after treatment; therefore, protective intervention and anti-malarial medications that immediately kill mature gametocytes could be recommended.

6572

CLIMATE CHANGE ADAPTATION MEASURES INFLUENCE HOUSEHOLD FOOD INSECURITY IN SOUTHERN ETHIOPIA

Taye Ayana1, Bethlehem Mezgebe1, Mehretu Belayneh1, Bernt Lindtjørn2

1Hawassa University, Hawassa, Ethiopia, 2University of Bergen, Bergen, Norway

As part of the project “Co-producing Gender-responsive Climate Services for Enhanced Food and Nutrition Security and Health (COGENT)” project in Ethiopia and Tanzania, we evaluated how the variation in rainfall and potential climate change adaptation measures influence household food insecurity. We did a quarterly survey involving 910 households from nine randomly selected rural kebeles (lowest political administration unit) in the Boricha district between June 2021 and March 2022. The data were collected using pretested, structured questionnaires, and potential causal links between weather variability, such as rainfall, and food insecurity were measured after controlling for possible confounding variables. The household food insecurity rate (HFI) was highest in June (89.3 %) and lowest in December (67.7 %) after the harvesting season. Months with high rainfall were followed by improved food security, coinciding with increased household wealth. Furthermore, the average Body Mass Index (BMI) in September was the lowest, followed by an increment of 0.35 in December 2021. Households whose heads had not attended formal education [Adjusted Odds Ratio (AOR) 6.02, 95 % confidence interval (CI) 4.70, 7.71], had low-income (AOR 1.30, 95 % CI 1.07, 1.57), households with poor dietary diversity score (AOR 1.43, 95% CI 1.21, 1.63), who were not beneficiaries of the Food safety net programme (AOR 1.77, 95 % CI 1.51, 2.01), and who were not members of the community-based health insurance (AOR 3.49, 95 % CI 2.83, 4.30) had higher risks of food insecurity. Our study shows that better education, higher economic status, participation in the Food safety net programme and community-based health insurance membership reduce the population’s vulnerability to food insecurity.