Spatiotemporal distribution and bionomics of Anopheles stephensi in different eco-epidemiological settings in Ethiopia.

BACKGROUND: Malaria is a major public health concern in Ethiopia, and its incidence could worsen with the spread of the invasive mosquito species Anopheles stephensi in the country. This study aimed to provide updates on the distribution of An. stephensi and likely household exposure in Ethiopia. METHODS: Entomological surveillance was performed in 26 urban settings in Ethiopia from 2021 to 2023. A kilometer-by-kilometer quadrant was established per town, and approximately 20 structures per quadrant were surveyed every 3 months. Additional extensive sampling was conducted in 50 randomly selected structures in four urban centers in 2022 and 2023 to assess households' exposure to An. stephensi. Prokopack aspirators and CDC light traps were used to collect adult mosquitoes, and standard dippers were used to collect immature stages. The collected mosquitoes were identified to species level by morphological keys and molecular methods. PCR assays were used to assess Plasmodium infection and mosquito blood meal source. RESULTS: Catches of adult An. stephensi were generally low (mean: 0.15 per trap), with eight positive sites among the 26 surveyed. This mosquito species was reported for the first time in Assosa, western Ethiopia. Anopheles stephensi was the predominant species in four of the eight positive sites, accounting for 75-100% relative abundance of the adult Anopheles catches. Household-level exposure, defined as the percentage of households with a peridomestic presence of An. stephensi, ranged from 18% in Metehara to 30% in Danan. Anopheles arabiensis was the predominant species in 20 of the 26 sites, accounting for 42.9-100% of the Anopheles catches. Bovine blood index, ovine blood index and human blood index values were 69.2%, 32.3% and 24.6%, respectively, for An. stephensi, and 65.4%, 46.7% and 35.8%, respectively, for An. arabiensis. None of the 197 An. stephensi mosquitoes assayed tested positive for Plasmodium sporozoite, while of the 1434 An. arabiensis mosquitoes assayed, 62 were positive for Plasmodium (10 for P. falciparum and 52 for P. vivax). CONCLUSIONS: This study shows that the geographical range of An. stephensi has expanded to western Ethiopia. Strongly zoophagic behavior coupled with low adult catches might explain the absence of Plasmodium infection. The level of household exposure to An. stephensi in this study varied across positive sites. Further research is needed to better understand the bionomics and contribution of An. stephensi to malaria transmission.

Dynamics of asymptomatic Plasmodium falciparum and Plasmodium vivax infections and their infectiousness to mosquitoes in a low transmission setting of Ethiopia: a longitudinal observational study.

OBJECTIVE: A 15-month longitudinal study was conducted to determine the duration and infectivity of asymptomatic qPCR-detected Plasmodium falciparum and Plasmodium vivax infections in Ethiopia. METHOD: Total parasite and gametocyte kinetics were determined by molecular methods; infectivity to Anopheles arabiensis mosquitoes by repeated membrane feeding assays. Infectivity results were contrasted with passively recruited symptomatic malaria cases. RESULTS: For P. falciparum and P. vivax infections detected at enrolment, median durations of infection were 37 days (95% confidence interval [CI], 15-93) and 60 days (95% CI, 18-213), respectively. P. falciparum and P. vivax parasite densities declined over the course of infections. From 47 feeding assays on 22 asymptomatic P. falciparum infections, 6.4% (3/47) were infectious and these infected 1.8% (29/1579) of mosquitoes. No transmission was observed in feeding assays on asymptomatic P. vivax mono-infections (0/56); one mixed-species infection was highly infectious. Among the symptomatic cases, 4.3% (2/47) of P. falciparum and 73.3% (53/86) of P. vivax patients were infectious to mosquitoes. CONCLUSION: The majority of asymptomatic infections were of short duration and low parasite density. Only a minority of asymptomatic individuals were infectious to mosquitoes. This contrasts with earlier findings and is plausibly due to the low parasite densities in this population.

Treatment outcomes of cutaneous leishmaniasis due to Leishmania aethiopica: A systematic review and meta-analysis.

BACKGROUND: Leishmania aethiopica is a unique species that causes cutaneous leishmaniasis (CL), and studies evaluating treatment outcomes for this condition reported inconsistent findings. This study aimed to summarize the evidence on treatment outcomes of CL caused by L. aethiopica to support decisions or propose further study. METHODS: We searched PubMed, Scopus, and ScienceDirect. In addition, we searched grey literature on Google Scholar and performed manual searching on the reference list of articles. Two authors did the screening, selection, critical appraisal, and data extraction. With the narrative synthesis of evidence, we performed a random effects model meta-analysis using the metaprop package in Stata 17. We did sensitivity and subgroup analyses after assessing heterogeneity using the I-squared test and forest plots. The funnel plot and Egger's test were used to assess publication bias. RESULTS: The review included 22 studies with 808 participants, and the meta-analysis included seven studies with 677 participants. Most studies documented treatment outcomes with antimonial monotherapy, and only one study reported outcomes with combination therapy. The overall pooled proportion of cure was 63% (95% CI: 38-86%). In the subgroup analysis, systemic antimonial monotherapy showed a cure rate of 61%, and the proportion of cure was 87% with topical therapy. Topical therapy showed a better cure for the localized clinical phenotype. A cohort study documented a cure rate of 94.8% with combination therapy for the localized, mucocutaneous, and diffuse clinical phenotypes. The pooled proportion of unfavourable outcomes was partial response (19%), relapse (17%), discontinuation (19%), and unresponsiveness (6%). CONCLUSIONS: The pooled proportion of cure is low with antimonial monotherapy. Despite limited evidence, combination therapies are a promising treatment option for all clinical phenotypes of CL caused by L. aethiopica. Future high-quality randomized control trials are needed to identify effective monotherapies and evaluate the effectiveness of combination therapies.

Health-related quality of life of adults with cutaneous leishmaniasis at ALERT Hospital, Addis Ababa, Ethiopia.

BACKGROUND: Cutaneous leishmaniasis (CL) is a growing public health threat in Ethiopia. Leishmania aethiopica is the predominant causative organism. Affected individuals develop chronic skin lesions on exposed parts of the body, mostly on the face, which are disfiguring and cause scarring. The effects of CL on the health-related quality of life (HRQoL) of affected individuals has not been assessed in Ethiopia. OBJECTIVE: To assess HRQoL in adults with active CL at ALERT Hospital, Addis Ababa, Ethiopia. METHODS: A cross-sectional study was done using the Amharic version of the Dermatology Life Quality Index (DLQI). Trained health staff administered the DLQI. RESULTS: Three hundred and two adults with active CL participated and all of them exhibited a reduced HRQoL. The median DLQI score was 10 (IQR 8). Almost half of the participants reported very poor HRQoL, 36.4% and 11.3% fell within the very large and extremely large effect categories respectively. DLQI scores were higher (median 18) in patients diagnosed with diffuse cutaneous leishmaniasis (DCL) compared to those with localized cutaneous leishmaniasis (LCL). The DLQI domain of 'work and school' was the most affected, scoring 73.3% and 66.6% of total possible score for female and male respectively, followed by that of 'symptom and feeling' (at 50.0% and 56.6% for female and male respectively). Men were more affected than women in the domains of 'leisure' (P = 0.002) and 'personal relationships' (P = 0.001). In the multivariate ordinal logistic regression site of lesion, clinical phenotype and age of participant remained associated with significantly poor HRQoL. CONCLUSION: The HRQoL impairment associated with CL is significant. Thus, patient-reported outcome measure should be used to assess the efficacy of treatments along with clinical outcome measures.

Perceptions and acceptability of co-administered albendazole, ivermectin and azithromycin mass drug administration, among the health workforce and recipient communities in Ethiopia.

Several neglected tropical diseases (NTDs) employ mass drug administration (MDA) as part of their control or elimination strategies. This has historically required multiple distinct campaigns, each targeting one or more NTDs, representing a strain on both the recipient communities and the local health workforce implementing the distribution. We explored perceptions and attitudes surrounding combined MDA among these two groups of stakeholders. Our qualitative study was nested within a cluster randomized non-inferiority safety trial of combined ivermectin, albendazole and azithromycin MDA. Using semi-structured question guides, we conducted 16 key informant interviews with selected individuals involved in implementing MDA within the participating district. To better understand the perceptions of recipient communities, we also conducted four focus group discussions with key community groups. Individuals were selected from both the trial arm (integrated MDA) and the control arm (standard MDA) to provide a means of comparison and discussion. All interviews and focus group discussions were led by fluent Afaan oromo speakers. Interviewers transcribed and later translated all discussions into English. The study team synthesized and analyzed the results via a coding framework and software. Most respondents appreciated the time and effort saved via the co-administered MDA strategy but there were some misgivings amongst community beneficiaries surrounding pill burden. Both the implementing health work force members and beneficiaries reported refusals stemming from lack of understanding around the need for the new drug regimen as well as some mistrust of government officials among the youth. The house-to-house distribution method, adopted as a COVID-19 prevention strategy, was by far preferred by all beneficiaries over central-point MDA, and may have led to greater acceptability of co-administration. Our data demonstrate that a co-administration strategy for NTDs is acceptable to both communities and health staff.

Malaria misdiagnosis in the routine health system in Arba Minch area district in southwest Ethiopia: an implication for malaria control and elimination.

BACKGROUND: Plasmodium falciparum and Plasmodium vivax are coendemic in Ethiopia, with different proportion in different settings. Microscopy is the diagnostic tool in Ethiopian health centres. Accurate species-specific diagnosis is vital for appropriate treatment of cases to interrupt its transmission. Therefore, this study assessed the status of species-specific misdiagnosis by microscope compared with polymerase chain reaction (PCR). METHODS: A health facility based cross-sectional study was conducted from November 2019 to January 2020 in Kolla Shelle Health centre, Arba Minch Zuria district. The study population were suspected malaria cases, who visited the health centre for a diagnosis and treatment. Consecutive microscopy positive cases as well as a sample of microscopically negative cases were included for molecular analysis by polymerase chain reaction (PCR). RESULTS: 254 microscopically negative and 193 microscopically positive malaria suspects were included. Of the 193 malaria positive cases, 46.1% [95% confidence interval (CI) 38.9-53.4] (89/193) were P. falciparum infection, 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, 3.4% (3/89) were P. vivax and 11.2% (10/89) were mixed infections with P. falciparum and P. vivax and a single case was negative molecularly. Similarly, of the microscopically positive P. vivax cases, 5.9% (6/101) were P. falciparum and 1% (1/101) was mixed infection. Single case was negative by molecular technique. Of the 254 microscopically negative cases, 0.8% were tested positive for P. falciparum and 2% for P. vivax by PCR. Considering molecular technique as a reference, the sensitivity of microscopy for detecting P. falciparum was 89.2% and for P. vivax, it was 91.2%. The specificity of microscopy for detecting P. falciparum was 96.1% and for P. vivax, it was 97.7%. However, the sensitivity of microscopy in detecting mixed infection of P. falciparum and P. vivax was low (8.3%). CONCLUSION: There were cases left untreated or inappropriately treated due to the species misidentification. Therefore, to minimize this problem, the gaps in the microscopic-based malaria diagnosis should be identified. It is recommended to regularly monitor the competency of malaria microscopists in the study area to improve species identification and diagnosis accuracy.

Trend analysis of malaria in urban settings in Ethiopia from 2014 to 2019.

BACKGROUND: Urbanization generally improves health outcomes of residents and is one of the potential factors that might contribute to reducing malaria transmission. However, the expansion of Anopheles stephensi, an urban malaria vector, poses a threat for malaria control and elimination efforts in Africa. In this paper, malaria trends in urban settings in Ethiopia from 2014 to 2019 are reported with a focus on towns and cities where An. stephensi surveys were conducted. METHODS: A retrospective study was conducted to determine malaria trends in urban districts using passive surveillance data collected at health facilities from 2014 to 2019. Data from 25 towns surveyed for An. stephensi were used in malaria trend analysis. Robust linear models were used to identify outliers and impute missing and anomalous data. The seasonal Mann-Kendal test was used to test for monotonic increasing or decreasing trends. RESULTS: A total of 9,468,970 malaria cases were reported between 2014 and 2019 through the Public Health Emergency Management (PHEM) system. Of these, 1.45 million (15.3%) cases were reported from urban settings. The incidence of malaria declined by 62% between 2014 and 2018. In 2019, the incidence increased to 15 per 1000 population from 11 to 1000 in 2018. Both confirmed (microscopy or RDT) Plasmodium falciparum (67%) and Plasmodium vivax (28%) were reported with a higher proportion of P. vivax infections in urban areas. In 2019, An. stephensi was detected in 17 towns where more than 19,804 malaria cases were reported, with most of the cases (56%) being P. falciparum. Trend analysis revealed that malaria cases increased in five towns in Afar and Somali administrative regions, decreased in nine towns, and had no obvious trend in the remaining three towns. CONCLUSION: The contribution of malaria in urban settings is not negligible in Ethiopia. With the rapid expansion of An. stephensi in the country, the receptivity is likely to be higher for malaria. Although the evidence presented in this study does not demonstrate a direct linkage between An. stephensi detection and an increase in urban malaria throughout the country, An. stephensi might contribute to an increase in malaria unless control measures are implemented as soon as possible. Targeted surveillance and effective response are needed to assess the contribution of this vector to malaria transmission and curb potential outbreaks.

Corrigendum to "Safety of integrated mass drug administration of azithromycin, albendazole and ivermectin versus standard treatment regimens: a cluster-randomised trial in Ethiopia".

[This corrects the article DOI: 10.1016/j.eclinm.2023.101984.].

Safety of integrated mass drug administration of azithromycin, albendazole and ivermectin versus standard treatment regimens: a cluster-randomised trial in Ethiopia.

Background: Neglected Tropical Disease (NTD) programs require separate and distinct drug regimens for treatment. This has required countries to undertake multiple independent mass drug administration (MDA) programmes, each targeting one or more diseases. The possibility of safely combining different drug regimens together in one MDA may offer several advantages to national programs. We conducted a study to assess the safety of combining ivermectin, albendazole and azithromycin in one integrated MDA. Methods: We conducted an open-label, non-inferiority cluster-randomised trial comparing the frequency of adverse events in communities receiving co-administered ivermectin, albendazole and azithromycin to that in communities given albendazole and ivermectin MDA followed by azithromycin MDA after a two-week interval. The study took place in 58 gares (small administrative units) across two kebeles (sub-districts) in Kofele woreda (district) in the Oromia region of Ethiopia. We randomly assigned 29 gares to the combined treatment arm and 29 gares to the control arm. The study team revisited all individuals within 48 h and actively collected data on the occurrence of adverse events using a dedicated questionnaire and a pre-specified list of adverse events. The study team followed the same process in the control arm for the azithromycin distribution and again after the ivermectin plus albendazole distribution. Following this initial active surveillance, passive surveillance was undertaken for one week after the first visit. The primary outcome was the frequency of adverse events occurring following MDA. The study team determined that the safety of the combined MDA would be non-inferior to that of separate MDAs if the upper limit of the two-sided CI for the difference in rates was equal to or lower than 5%. The trial was registered with ClinicalTrials.gov, NCT03570814. Findings: The study took place from December 2021 to January 2022. The combined MDA arm consisted of 7292 individuals who were eligible to participate, of whom 7068 received all three medications. The separate MDA arm consisted of 6219 eligible individuals of whom 6211 received ivermectin and albendazole and 4611 received azithromycin two weeks later. Overall, adverse events were reported by 197 (1.2%) of individuals. The most commonly reported adverse events included headache, gastrointestinal disturbance and dizziness. There were no serious adverse events in either arm. The cluster-level mean frequency of reported adverse events varied markedly between clusters, ranging from 0.1 to 10.4%. The cluster-level mean frequency of adverse events was 1.4% in the combined MDA arm and 1.2% following ivermectin and albendazole MDA (absolute difference 0.2%, 95% confidence interval [CI] -0.6% to +1.1%). This met the pre-defined 1.5% non-inferiority margin. For the combined MDA comparison to the stand-alone azithromycin MDA the absolute difference was -0.4% (1.4 versus 1.8%, 95% CI -0.8 to +1.5) which also met the pre-specified non-inferiority margin. Interpretation: This study is the largest of its kind to date and demonstrates that the safety of combined MDA of azithromycin, ivermectin and albendazole is non-inferior to the safety of ivermectin-plus-albendazole MDA then azithromycin MDA conducted separately although we may not have been powered to detect very small differences between arms. Co-administration of these three medicines is safe and feasible in this setting and allows national programs to develop new strategies for integrated MDA programs. Funding: Ivermectin (Mectizan) was donated by the Mectizan Donation Program, albendazole was donated by GlaxoSmithKline, and azithromycin (Zithromax®) was donated by Pfizer via the International Trachoma Initiative (ITI). The trial was funded by ITI using operational research funds from the Bill and Melinda Gates Foundation.

Treatment of uncomplicated Plasmodium vivax with chloroquine plus radical cure with primaquine without G6PDd testing is safe in Arba Minch, Ethiopia: assessment of clinical and parasitological response.

BACKGROUND: Ethiopia rolled out primaquine nationwide in 2018 for radical cure along with chloroquine for the treatment of uncomplicated Plasmodium vivax malaria in its bid for malaria elimination by 2030. The emergence of anti-malarial drug resistance would challenge the elimination goal. There is limited evidence on the emergence of chloroquine drug resistance. The clinical and parasitological outcomes of treatment of P. vivax with chloroquine plus radical cure using low dose 14 days primaquine were assessed in an endemic area of Ethiopia. METHODS: A semi-directly observed 42-days follow up in-vivo therapeutic efficacy study was conducted from October 2019 to February 2020. Plasmodium vivax mono-species infected patients (n = 102) treated with a 14 days low dose (0.25 mg/kg body weight per day) primaquine plus chloroquine (a total dose of 25 mg base/kg for 3 days) were followed for 42 days to examine clinical and parasitological outcomes. Samples collected at recruitment and days of recurrence were examined by 18 S based nested polymerase chain reaction (nPCR) and Pvmsp3α nPCR-restriction fragment length polymorphism. Asexual parasitaemia and the presence of gametocytes were assessed on the scheduled days using microscopy. Clinical symptoms, haemoglobin levels, and Hillmen urine test were also assessed. RESULTS: Of the 102 patients followed in this study, no early clinical and parasitological failure was observed. All patients had adequate clinical and parasitological responses within the 28 days of follow up. Late clinical (n = 3) and parasitological (n = 6) failures were observed only after day 28. The cumulative incidence of failure was 10.9% (95% confidence interval, 5.8-19.9%) on day 42. Among the paired recurrent samples, identical clones were detected only in two samples on day 0 and day of recurrences (day 30 and 42) using Pvmsp3α genotyping. No adverse effect was detected related to the low dose 14 days primaquine administrations. CONCLUSION: Co-administration of CQ with PQ in the study area is well tolerated and there was no recurrence of P. vivax before 28 days of follow up. Interpretation of CQ plus PQ efficacy should be done with caution especially when the recurrent parasitaemia occurs after day 28. Therapeutic efficacy studies with appropriate design might be informative to rule out chloroquine or primaquine drug resistance and/or metabolism in the study area.

Evaluation of the effect of targeted Mass Drug Administration and Reactive Case Detection on malaria transmission and elimination in Eastern Hararghe zone, Oromia, Ethiopia: a cluster randomized control trial.

BACKGROUND: Reactive and proactive case detection measures are widely implemented by national malaria elimination programs globally. Ethiopia decided to include Reactive Case Detection (RCD) and targeted Mass Drug Administration (tMDA) approaches as part of their elimination strategy along with rigorous evaluation. The purpose of this study is to compare the impact of RCD and tMDA on malaria elimination over the 2-year study period, by looking at the annual parasite incidence before and after the intervention. METHODS: The study will be conducted in the East Hararghe zone of Ethiopia. Malaria transmission in the area is low to moderate. This study will deploy a community-based, three-arm, cluster-randomized control trial implemented over 2 years. Forty-eight clusters (16 clusters per arm) will be selected based on the annual number of confirmed malaria cases seen in the cluster. All clusters will receive the current standard of care in terms of malaria elimination interventions provided by the national malaria control program. In addition, following the identification of malaria parasite infection, individuals who reside within a 100-m radius of the index case will receive a diagnosis for malaria and treatment if positive in the RCD arm or presumptive treatment in the tMDA arm. The primary effectiveness endpoint will be measured at baseline and endline for each intervention arm and compared to the control arm using a difference in difference approach. DISCUSSION: This randomized controlled trial will provide evidence of the impact of the proposed intervention approaches for malaria elimination. TRIAL REGISTRATION: ClinicalTrials.gov NCT04241705 . Registration date: January 27, 2020.

Cytotoxic and other bioactivities of a novel and known sesquiterpene lactones isolated from Vernonia leopoldi (Sch. Bip. ex Walp.) Vatke in breast cancer cell lines.

Vernonia leopoldi (Sch. Bip. ex Walp.) Vatke (Asteraceae) is one of the widely used anti-cancer traditional medicinal plants in Ethiopia, despite the lack of data to support its therapeutic efficacy. Here we describe the isolation of compounds from the plant and the investigation of their cytotoxicity and other bioactivities. We identified the novel sesquiterpene lactone (SL) 11ß,13-dihydrovernodalol along with the three other SLs (vernomenin, vernolepin, and 11ß,13-dihydrovernodalin) and three flavonoids (apigenin, eriodyctiol, and luteolin) isolated from this plant for the first time. The structures of all the compounds were established based on extensive analysis of nuclear magnetic resonance spectroscopic data and confirmed by high-resolution electrospray ionization mass spectrometry. We then studied the biological activities of the SLs and found that all were cytotoxic at low µM ranges against MCF-7 and JIMT-1 breast cancer cells as well as against the normal-like MCF-10A breast epithelial cells evaluated in a spectrophotometric assay. All the SLs significantly reduced JIMT-1 cell migration after 72 h of treatment with 2 µM concentrations in a wound healing assay. Treatment with all SLs reduced the aldehyde dehydrogenase expressing cancer stem cell sub-population of the JIMT-1 cells significantly, evaluated by flow cytometry. Only 11ß,13-dihydrovernodalin resulted in a significant inhibition of tumor necrosis factor-α-induced translocation of nuclear factor κB to the cell nucleus. In addition, we show that the reporter fluorophore nitrobenzoxadiazole (NBD) can successfully be conjugated with an SL and that this SL-NBD conjugate is taken up efficiently in JIMT-1 cells. Therefore, the overall bioactivities of the SL compounds and specifically their effects against the stemness of breast cancer cells make them prime candidates for further in-depth investigation.

A comparison of PCR and ELISA methods to detect different stages of Plasmodium vivax in Anopheles arabiensis.

BACKGROUND: In characterizing malaria epidemiology, measuring mosquito infectiousness informs the entomological inoculation rate, an important metric of malaria transmission. PCR-based methods have been touted as more sensitive than the current "gold-standard" circumsporozoite (CSP) ELISA. Wider application of PCR-based methods has been limited by lack of specificity for the infectious sporozoite stage. We compared a PCR method for detecting the parasite's mitochondrial (mt) cytochrome oxidase I (COX-I) gene with ELISA for detecting circumsporozoite protein for identification of different life stages of the parasite during development within a mosquito. METHODS: A PCR-based method targeting the Plasmodium mt COX-I gene was compared with the CSP ELISA method to assess infectivity in Anopheles arabiensis colony mosquitoes fed on blood from patients infected with Plasmodium vivax. Mosquitoes were tested at six post-infection time points (days 0.5, 1, 6, 9, 12, 15). The head and thorax and the abdomen for each specimen were tested separately with each method. Agreement between methods at each infection stage was measured using Cohen's kappa measure of test association. RESULTS: Infection status of mosquitoes was assessed in approximately 90 head/thorax and 90 abdomen segments at each time point; in total, 538 head/thorax and 534 abdomen segments were tested. In mosquitoes bisected after 0.5, 1, and 6 days post-infection (dpi), the mt COX-I PCR detected Plasmodium DNA in both the abdomen (88, 78, and 67%, respectively) and head/thorax segments (69, 60, and 44%, respectively), whilst CSP ELISA detected sporozoites in only one abdomen on day 6 post-infection. PCR was also more sensitive than ELISA for detection of Plasmodium in mosquitoes bisected after 9, 12, and 15 dpi in both the head and thorax and abdomen. There was fair agreement between methods for time points 9-15 dpi (κ = 0.312, 95% CI: 0.230-0.394). CONCLUSIONS: The mt COX-I PCR is a highly sensitive, robust method for detecting Plasmodium DNA in mosquitoes, but its limited Plasmodium life-stage specificity cannot be overcome by bisection of the head and thorax from the abdomen prior to PCR. Thus, the mt COX-I PCR is a poor candidate for identifying infectious mosquitoes.

An update on the distribution, bionomics, and insecticide susceptibility of Anopheles stephensi in Ethiopia, 2018-2020.

BACKGROUND: Anopheles stephensi, an invasive malaria vector, was first detected in Africa nearly 10 years ago. After the initial finding in Djibouti, it has subsequently been found in Ethiopia, Sudan and Somalia. To better inform policies and vector control decisions, it is important to understand the distribution, bionomics, insecticide susceptibility, and transmission potential of An. stephensi. These aspects were studied as part of routine entomological monitoring in Ethiopia between 2018 and 2020. METHODS: Adult mosquitoes were collected using human landing collections, pyrethrum spray catches, CDC light traps, animal-baited tent traps, resting boxes, and manual aspiration from animal shelters. Larvae were collected using hand-held dippers. The source of blood in blood-fed mosquitoes and the presence of sporozoites was assessed through enzyme-linked immunosorbent assays (ELISA). Insecticide susceptibility was assessed for pyrethroids, organophosphates and carbamates. RESULTS: Adult An. stephensi were collected with aspiration, black resting boxes, and animal-baited traps collecting the highest numbers of mosquitoes. Although sampling efforts were geographically widespread, An. stephensi larvae were collected in urban and rural sites in eastern Ethiopia, but An. stephensi larvae were not found in western Ethiopian sites. Blood-meal analysis revealed a high proportion of blood meals that were taken from goats, and only a small proportion from humans. Plasmodium vivax was detected in wild-collected An. stephensi. High levels of insecticide resistance were detected to pyrethroids, carbamates and organophosphates. Pre-exposure to piperonyl butoxide increased susceptibility to pyrethroids. Larvae were found to be susceptible to temephos. CONCLUSIONS: Understanding the bionomics, insecticide susceptibility and distribution of An. stephensi will improve the quality of a national response in Ethiopia and provide additional information on populations of this invasive species in Africa. Further work is needed to understand the role that An. stephensi will have in Plasmodium transmission and malaria case incidence. While additional data are being collected, national programmes can use the available data to formulate and operationalize national strategies against the threat of An. stephensi.

Enhanced activation of blood neutrophils and monocytes in patients with Ethiopian localized cutaneous leishmaniasis in response to Leishmania aethiopica Neutrophil activation in Ethiopian cutaneous leishmaniasis.

Recent studies suggest an essential role of the innate immune effector cells neutrophils and monocytes in protection or disease progression in the early course of Leishmania infection. In areas endemic for cutaneous leishmaniasis in Ethiopia most individuals are exposed to bites of infected sandflies. Still only a minor ratio of the inhabitants develops symptomatic disease. Neutrophils, followed by monocytes, are the first cells to be recruited to the site of Leishmania infection, the initial response of neutrophils to parasites appears to be crucial for the protective response and disease outcome. Our working hypothesis is that neutrophils and/or monocytes in localized cutaneous leishmaniasis (LCL) patients may have defects in function of innate immune cell that contribute to failure to parasite clearance that lead to establishment of infection. The response of cells in Ethiopian LCL patients and healthy controls to Leishmania aethiopica and to the Toll like receptor (TLR) agonists lipopolysaccharide (LPS) and macrophage activating lipopeptide-2 (MALP-2) was investigated by assessing the cell surface expression of CD62L (on neutrophil and monocyte) and CD66b (only on neutrophil), as well as reactive oxygen species (ROS) production by using whole blood-based assays in vitro. No impaired response of neutrophils and monocytes to the microbial constituents LPS and MALP-2 was observed. Neutrophils and monocytes from LCL patients responded stronger to Leishmania aethiopica in the applied whole blood assays than cells from healthy individuals. These experimental findings do not support the hypothesis regarding a possible dysfunction of neutrophils and monocytes in cutaneous leishmaniasis. On the contrary, these cells react stronger in LCL patients as compared to healthy controls. The differential response to L. aethiopica observed between LCL patients and healthy controls have the potential to serve as biomarker to develop FACS based diagnostic/ prognostic techniques for LCL.

Past eight-year malaria data in Gedeo zone, southern Ethiopia: trend, reporting-quality, spatiotemporal distribution, and association with socio-demographic and meteorological variables.

BACKGROUND: Informed decision making is underlined by all tiers in the health system. Poor data record system coupled with under- (over)-reporting of malaria cases affects the country's malaria elimination activities. Thus, malaria data at health facilities and health offices are important particularly to monitor and evaluate the elimination progresses. This study was intended to assess overall reported malaria cases, reporting quality, spatiotemporal trends and factors associated in Gedeo zone, South Ethiopia. METHODS: Past 8 years retrospective data stored in 17 health centers and 5 district health offices in Gedeo Zone, South Ethiopia were extracted. Malaria cases data at each health center with sociodemographic information, between January 2012 and December 2019, were included. Meteorological data were obtained from the national meteorology agency of Ethiopia. The data were analyzed using Stata 13. RESULTS: A total of 485,414 suspected cases were examined for malaria during the previous 8 years at health centers. Of these suspects, 57,228 (11.79%) were confirmed malaria cases with an overall decline during the 8-year period. We noted that 3758 suspected cases and 467 confirmed malaria cases were not captured at the health offices. Based on the health centers records, the proportions of Plasmodium falciparum (49.74%) and P. vivax (47.59%) infection were nearly equivalent (p = 0.795). The former was higher at low altitudes while the latter was higher at higher altitudes. The over 15 years of age group accounted for 11.47% of confirmed malaria cases (p < 0.001). There was high spatiotemporal variation: the highest case record was during Belg (12.52%) and in Dilla town (18,150, 13.17%, p < 0.001) which is located at low altitude. Monthly rainfall and minimum temperature exhibited strong associations with confirmed malaria cases. CONCLUSION: A notable overall decline in malaria cases was observed during the eight-year period. Both P. falciparum and P. vivax were found at equivalent endemicity level; hence control measures should continue targeting both species. The noticed under reporting, the high malaria burden in urban settings, low altitudes and Belg season need spatiotemporal consideration by the elimination program.

Prevalence of asymptomatic visceral leishmaniasis in human and dog, Benishangul Gumuz regional state, Western Ethiopia.

BACKGROUND: The Benishangul-Gumuz region is an important development corridor in Ethiopia. Large-scale projects such as the Great Renaissance Dam, mining and agriculture have entailed huge environmental modifications and settlement pattern changes. There is no detailed epidemiological information on visceral leishmaniasis (VL) in the region. MATERIALS AND METHODS: A cross-sectional study was carried out to assess the epidemiology and risk factors associated with Leishmania infection. A leishmanin skin test (LST) was done for 1342 participants, and for 253 of them rK39 and DAT were carried out. Thirty-six dogs owned by households with LST-positive member(s) were rK39 and DAT tested. A pretested questionnaire was used to capture individual and household characteristics. RESULTS: Of the 89.2% (1197/1342) who availed themselves of the LST reading, 6.0% were positive. The rk39 and DAT positivity among the 253 tested were 3.2% and 5.9%, respectively. In dogs, positivity rates by rK39 and DAT were 13.9% and 5.6%, respectively. Of the household and individual risk factors, presence of a dog in the household (P = 0.005), male sex (0.003), residence woreda (0.000) and occupation (0.023) showed a strong positive association with LST positivity. Individuals who lived in households that had dogs were 2.6 times more likely to be LST positive (AOR = 2.6; 95% CI = 1.54, 4.40). Being female decreased the probability of being LST positive by 0.38 times (AOR = 0.38; 95% CI = 0.20, 0.72). People living in Guba and Kurmuk had 4.7 (AOR = 4.74, 95% CI 1.83, 12.31) and 5.9 (AOR = 5.85, 95% CI 2.27, 15.09) times more risk of being infected. CONCLUSIONS: We demonstrated the presence of active VL transmission in the areas. Thus, we underline the need to establish the responsible vector(s) and reservoir(s) for comprehensive early containment plans to prevent potentially harmful public health and economic consequences.

The epidemiology and detectability of asymptomatic plasmodium vivax and plasmodium falciparum infections in low, moderate and high transmission settings in Ethiopia.

BACKGROUND: As countries move to malaria elimination, detecting and targeting asymptomatic malaria infections might be needed. Here, the epidemiology and detectability of asymptomatic Plasmodium falciparum and Plasmodium vivax infections were investigated in different transmission settings in Ethiopia. METHOD: A total of 1093 dried blood spot (DBS) samples were collected from afebrile and apparently healthy individuals across ten study sites in Ethiopia from 2016 to 2020. Of these, 862 were from community and 231 from school based cross-sectional surveys. Malaria infection status was determined by microscopy or rapid diagnostics tests (RDT) and 18S rRNA-based nested PCR (nPCR). The annual parasite index (API) was used to classify endemicity as low (API > 0 and < 5), moderate (API ≥ 5 and < 100) and high transmission (API ≥ 100) and detectability of infections was assessed in these settings. RESULTS: In community surveys, the overall prevalence of asymptomatic Plasmodium infections by microscopy/RDT, nPCR and all methods combined was 12.2% (105/860), 21.6% (183/846) and 24.1% (208/862), respectively. The proportion of nPCR positive infections that was detectable by microscopy/RDT was 48.7% (73/150) for P. falciparum and 4.6% (2/44) for P. vivax. Compared to low transmission settings, the likelihood of detecting infections by microscopy/RDT was increased in moderate (Adjusted odds ratio [AOR]: 3.4; 95% confidence interval [95% CI] 1.6-7.2, P = 0.002) and high endemic settings (AOR = 5.1; 95% CI 2.6-9.9, P < 0.001). After adjustment for site and correlation between observations from the same survey, the likelihood of detecting asymptomatic infections by microscopy/RDT (AOR per year increase = 0.95, 95% CI 0.9-1.0, P = 0.013) declined with age. CONCLUSIONS: Conventional diagnostics missed nearly half of the asymptomatic Plasmodium reservoir detected by nPCR. The detectability of infections was particularly low in older age groups and low transmission settings. These findings highlight the need for sensitive diagnostic tools to detect the entire parasite reservoir and potential infection transmitters.

Anopheles stephensi Mosquitoes as Vectors of Plasmodium vivax and falciparum, Horn of Africa, 2019.

Anopheles stephensi mosquitoes, efficient vectors in parts of Asia and Africa, were found in 75.3% of water sources surveyed and contributed to 80.9% of wild-caught Anopheles mosquitoes in Awash Sebat Kilo, Ethiopia. High susceptibility of these mosquitoes to Plasmodium falciparum and vivax infection presents a challenge for malaria control in the Horn of Africa.