MALARIA VECTOR CONTROL HISTORY AND CHALLENGES IN ETHIOPIA: MINI REVIEW

In Ethiopia, malaria has been an ancient and historical vector-borne disease. Over 75% of the land surface is malarious, and around 60% of the population is malaria at risk with varying intensity. In 1966, concerted eradication efforts began with the motivation being to eradicate malaria from Ethiopia by 1980. And indoor residual spray (IRS) with Dichloro Diphenyl Trichloroethane (DDT) and trained local staff on vector control methods was the main focus. However, malaria prevalence increased, and the major epidemic occurs every 5-8 years. It manifests a significant problem to the economic and social development of the country. The government directed a malaria control action plan under the objectives of Roll Back Malaria (RBM), which guided prevention and control activities. Between 2005 to 2018, Ethiopia distributed around 100 million long-lasting insecticide nets (LLINs), and 93.7% of the at-risk population were protected up to 2018 by the IRS. The malaria prevalence rate in 2011 was 1.3 whereas, in 2015, it decreased to 0.5. Ethiopia plans to achieve nationwide malaria elimination by 2030. Malaria is still public health threaten disease & accounts for 30% of the overall disability-adjusted life years lost in Ethiopia. And vector control interventions effectiveness has a serious obstacle due to resistance development to all available insecticide and the flexibility of Anopheles mosquito species behavior. Focuses on the history of malaria eradication and control and the controversial issues in malaria elimination. Requires thoughtful consideration of all risks, benefits, and challenges

Prevalence of Trachoma in Northern Benin: Results from 11 Population-Based Prevalence Surveys Covering 26 Districts.

AIMS: We sought to evaluate trachoma prevalence in all suspected-endemic areas of Benin. METHODS: We conducted population-based surveys covering 26 districts grouped into 11 evaluation units (EUs), using a two-stage, systematic and random, cluster sampling design powered at EU level. In each EU, 23 villages were systematically selected with population proportional to size; 30 households were selected from each village using compact segment sampling. In selected households, we examined all consenting residents aged one year or above for trichiasis, trachomatous inflammation - follicular (TF), and trachomatous inflammation - intense. We calculated the EU-level backlog of trichiasis and delineated the ophthalmic workforce in each EU using local interviews and telephone surveys. RESULTS: At EU-level, the TF prevalence in 1-9-year-olds ranged from 1.9 to 24.0%, with four EUs (incorporating eight districts) demonstrating prevalences ≥5%. The prevalence of trichiasis in adults aged 15+ years ranged from 0.1 to 1.9%. In nine EUs (incorporating 19 districts), the trichiasis prevalence in adults was ≥0.2%. An estimated 11,457 people have trichiasis in an area served by eight ophthalmic clinical officers. CONCLUSION: In northern Benin, over 8000 people need surgery or other interventions for trichiasis to reach the trichiasis elimination threshold prevalence in each EU, and just over one million people need a combination of antibiotics, facial cleanliness and environmental improvement for the purposes of trachoma's elimination as a public health problem. The current distribution of ophthalmic clinical officers does not match surgical needs

Risk Factors for Chikungunya Virus Outbreak in Somali Region of Ethiopia, 2019: Unmatched Case-Control Study

Background. Chikungunya virus is a ribonucleic acid (RNA) virus transmitted by a mosquito bite. Chikungunya virus outbreaks are characterized by rapid spread, and the disease manifests as acute fever. This study aimed at determining risk factors for chikungunya virus outbreak to apply appropriate prevention and control measures. Methods. Unmatched case-control study was performed to identify risk factors of chikungunya outbreak in Somali region of Ethiopia in 2019. Cases and controls were enrolled with 1 : 2 ratio. All cases during the study period (74 cases) and 148 controls were included in the study. Bivariate and multivariable analyses were implemented. The serum samples were tested by real-time polymerase chain reaction at Ethiopian Public Health Institute Laboratory. Results. A total of 74 chikungunya fever cases were reported starting from 19th May 2019 to 8th June 2019. Not using bed net at daytime sleeping (adjusted odds ratio (AOR): 20.8; 95% confidence interval (CI): 6.4–66.7), presence of open water holding container (AOR: 4.0; CI: 1.2–3.5), presence of larvae in water holding container (AOR: 4.8; CI: 1.4–16.8), ill person with similar signs and symptoms in the family or neighbors (AOR: 27.9; CI: 6.5–120.4), and not wearing full body cover clothes (AOR: 8.1; CI: 2.2–30.1) were significant risk factors. Conclusion. Not using bed net at daytime sleeping, presence of open water holding container, presence of larvae in water holding container, ill person with similar signs and symptoms in the family or neighbors, and not wearing full body cover clothes are risk factors for chikungunya virus outbreak

Malaria vector feeding, peak biting time and resting place preference behaviors in line with Indoor based intervention tools and its implication: scenario from selected sentinel sites of Ethiopia

In Ethiopia, malaria incidence has significantly reduced in the past decade through the combined use of conventional vector control approaches and treatment using antimalarial drugs. However, the sustainability of this achievement is threatened by the shift in biting and resting behaviors and emergence of insecticide resistance by the primary malaria vector. Therefore, continuous monitoring of the behaviour of malaria mosquitoes in different sentinel sites is crucial to design effective prevention and control methods in the local context. Entomological investigations were conducted in three sentinel sites for five consecutive months during the major malaria transmission season. The species composition, population dynamics, biting and resting behaviours of malaria vectors were determined using center for disease control and prevention (CDC) light trap, human landing catch (HLC), pyrethrum spray catch (PSC) and Pitfall shelter collection (PFS). Accordingly, 10 households for CDC, 10 households for PSC, 10 households for PFS and 5 households for HLC from each site were randomly enrolled for mosquito collection. A total of 8,297 anopheline mosquitoes were collected from the three sites, out of which 4,525 (54.5 %) were An. gambiae, s.l. 2,028 (24.4 %) were An. pharoensis, 160 (1.9 %) were An. funestus and the rest 1,584 (19 %) were other anophelines (An. coustani, An. cinerus and An. tenebrosus). No significant variation (P = 0.476) was observed between indoor (25.2/trap-night and outdoor collections (20.1/trap-night). Six hundred seventy six (43.3%) of An. gambiae s.l. (primary vector) were collected between 18:00 and 22:00 h. Biting activity declined between 00:00 and 02:00 h. The national malaria control program should pay close attention to the shifting behavior of vector mosquitoes as the observed outdoor feeding tendency of the vector population could pose challenges to the indoor intervention tools IRS and LLINs

Epidemiological, Entomological, and Climatological Investigation of the 2019 Dengue Fever Outbreak in Gewane District, Afar Region, North-East Ethiopia

Dengue Fever (DF) is an important arthropod-borne viral infection that has repeatedly occurred as outbreaks in eastern and northeastern Ethiopia since 2013. A cross-sectional epidemiological outbreak investigation was carried out from September to November 2019 on febrile patients (confirmed malaria negative) who presented with suspected and confirmed DF at both public and private health facilities in Gewane District, Afar Region, northeastern Ethiopia. Entomological investigation of containers found in randomly selected houses belonging to DF-positive patients was undertaken to survey for the presence of Aedes larvae/pupae. A total of 1185 DF cases were recorded from six health facilities during the 3-month study period. The mean age of DF cases was 27.2 years, and 42.7% of cases were female. The most affected age group was 15–49 years old (78.98%). The total case proportions differed significantly across age groups when compared to the population distribution; there were approximately 15% and 5% higher case proportions among those aged 15–49 years and 49+ years, respectively. A total of 162 artificial containers were inspected from 62 houses, with 49.4% found positive for Aedes aegypti larva/pupae. Aedes mosquitoes were most commonly observed breeding in plastic tanks, tires, and plastic or metal buckets/bowls. World Health Organization entomological indices classified the study site as high risk for dengue virus outbreaks (House Index = 45.2%, Container Index = 49.4%, and Breteau Index = 129). Time series climate data, specifically rainfall, were found to be significantly predictive of AR (p = 0.035). Study findings highlight the importance of vector control to prevent future DF outbreaks in the region. The scarcity of drinking water and microclimatic conditions may have also contributed to the occurrence of this outbreak

Molecular detection and antimicrobial resistance profile of Salmonella isolated from humans, animals, abattoir equipment and environment

Abattoir environments and poor slaughtering practices could serve as source of contamination with Salmonella species and their antimicrobial resistant genes, thereby affecting the animal-origin food system, and public health. This study aimed to isolate, and molecularly detect Salmonella species from humans, slaughtered animals, and from slaughtering equipment and environment, as well as to assess antimicrobial resistance profile of Salmonella isolates. A cross-sectional study was conducted at three abattoir settings, from September 2020 to February 2021. A total of 240 pooled swab samples were collected from the hands and cloths of abattoir workers, slaughtering areas, knives and from carcass; including water samples. Bacteriological techniques were employed to isolate presumed Salmonella species; while conventional and multiplex polymerase chain reactions (PCRs) were performed to confirm the genus Salmonella, Salmonella Enteritidis and S. Typhimurium. The Kirby-Buaer disk diffusion method was used to test antimicrobial susceptibility of confirmed Salmonella isolates. Based on bacteriological and biochemical tests, an overall 9.2 %(22/240) of Salmonella species were isolated, out of which 40.9 %(9/22) were found containing histidine transport operon gene. Among the nine Salmonella isolates, eight, six, six, five, and four isolates were found resistant to ampicillin, cefoxitin, tetracycline, Co-trimoxazole, and doxycycline hydrochloride, respectively. Furthermore, six of the Salmonella isolates showed multidrug resistance. The study showed presence of potential contamination of abattoir settings with antimicrobial resistant Salmonella isolates. With existing poor hygiene and sanitation practices, this might indicate risks for people consuming meat and for animals having access to contaminated environments