Last data update: Mar 21, 2025. (Total: 48935 publications since 2009)
Records 1-22 (of 22 Records) |
Query Trace: Mumba M[original query] |
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An observational study evaluating the epidemiological and entomological impacts of piperonyl butoxide insecticide-treated nets (ITNs) compared to a combination of indoor residual spraying (IRS) plus standard pyrethroid-only ITNs in Amhara Region, Ethiopia, 2019-2023
Davis KM , Worku A , Balkew M , Mumba P , Chibsa S , Tongren JE , Assefa G , Sisay A , Teshome D , Tegegne B , Worku M , Yimer M , Yewhalaw D , Yoshimizu M , Zohdy S , Swamidoss I , Mapp C , Hwang J , Inouye W , Seyoum A , Flatley C , Hilton ER , Dengela D , Burnett SM . BMJ Glob Health 2025 10 (1) INTRODUCTION: National malaria programmes must weigh the relative benefits of different vector control and elimination tools to prioritise resource allocation with the greatest impact. This study assesses the epidemiological and entomological impacts of piperonyl butoxide insecticide-treated nets (PBO ITN-only arm) compared with the combination of two annual non-pyrethroid indoor residual spraying (IRS) campaigns and standard pyrethroid ITNs (IRS+Standard Pyrethroid ITN arm) in the Amhara region of Ethiopia. METHODS: An open-label, stratified block-cluster randomised trial was designed to compare the impacts of the two intervention arms. ITN distribution took place from June to July 2021. IRS campaigns took place from June to July 2021 and again in June 2022. Confirmed malaria cases reported during the high transmission season (September to December) were compared in the 2 years before (2019 and 2020) vs the 2 years after (2021 and 2022) the 2021 campaigns. The difference in An. gambiae s.l. vector density per trap and indoor resting density (IRD) was assessed between the two arms during the high transmission seasons 2 years after the 2021 campaigns. RESULTS: Estimated malaria cases decreased significantly by 53.6% in the postintervention period compared with preintervention in the IRS+Standard Pyrethroid ITN arm (95% CI -72.9%, -29.8%) and by 55.9% in the PBO ITN arm (95% CI -73.0%, -32.5%), with no significant difference between these two arms (95% CI -30.9%, 24.0%). From the first to the second season postintervention, cases decreased non-significantly in the IRS+Standard Pyrethroid ITN arm (incidence rate ratio (IRR) 0.94; 95% CI 0.66, 1.47) but increased significantly in the PBO ITN arm (IRR 1.98; 95% CI 1.49, 2.67). Postintervention vector density and IRD were not found to be significantly different between intervention arms in either 2021 (vector density: IRR 0.78; 95% CI 0.47, 1.31; IRD: IRR 0.80; 95% CI 0.37, 1.75) or 2022 (vector density: IRR 1.27; 95% CI 0.75, 2.12; IRD: IRR 1.02; 95% CI 0.45, 2.28). CONCLUSION: These findings suggest a positive impact of non-pyrethroid IRS deployed annually alongside standard pyrethroid ITNs in a setting of confirmed pyrethroid resistance. While an overall positive impact of PBO ITNs was detected, a waning impact of the nets 2 years postdistribution was observed. |
Evidence for a role of Anopheles stephensi in the spread of drug and diagnosis-resistant malaria in Africa
Emiru T , Getachew D , Murphy M , Sedda L , Ejigu LA , Bulto MG , Byrne I , Demisse M , Abdo M , Chali W , Elliott A , Vickers EN , Aranda-Díaz A , Alemayehu L , Behaksera SW , Jebessa G , Dinka H , Tsegaye T , Teka H , Chibsa S , Mumba P , Girma S , Hwang J , Yoshimizu M , Sutcliffe A , Taffese HS , Bayissa GA , Zohdy S , Tongren JE , Drakeley C , Greenhouse B , Bousema T , Tadesse FG . Nat Med 2023 29 (12) 3203-3211 ![]() Anopheles stephensi, an Asian malaria vector, continues to expand across Africa. The vector is now firmly established in urban settings in the Horn of Africa. Its presence in areas where malaria resurged suggested a possible role in causing malaria outbreaks. Here, using a prospective case-control design, we investigated the role of An. stephensi in transmission following a malaria outbreak in Dire Dawa, Ethiopia in April-July 2022. Screening contacts of patients with malaria and febrile controls revealed spatial clustering of Plasmodium falciparum infections around patients with malaria in strong association with the presence of An. stephensi in the household vicinity. Plasmodium sporozoites were detected in these mosquitoes. This outbreak involved clonal propagation of parasites with molecular signatures of artemisinin and diagnostic resistance. To our knowledge, this study provides the strongest evidence so far for a role of An. stephensi in driving an urban malaria outbreak in Africa, highlighting the major public health threat posed by this fast-spreading mosquito. |
Developing and validating a screening tool for female genital schistosomiasis in urban Zambia
Rogers EQ , Mwangelwa S , Kabengele C , Kilembe W , Vwalika B , Inambao M , Mumba K , Chanda C , Secor WE , Musale V , Himukumbwa C , Parker R , Tichacek A , Bougouma K , Allen S , Wall KM . Front Trop Dis 2023 4 Background: The World Health Organization estimates that 56 million women and girls live with female genital schistosomiasis (FGS) in sub-Saharan Africa. FGS is often confused with symptoms of other genital abnormalities, and gold standard diagnosis with colposcopy is infeasible in most health facilities. Schistosomiasis haematobium is endemic in Zambia, yet routine screening or diagnostic efforts for FGS remain unavailable. Our study aimed to develop and pilot test a feasible FGS screening algorithm to implement in Zambian government clinics. Methodology/Principal Findings: We recruited 499 women from a longitudinal cohort of HIV-negative adult women in Lusaka and Ndola, Zambia. We used demographic, risk factor, and symptom data collected from standardized surveys, gynecological exams, and laboratory tests to develop a screening algorithm for FGS among a derivation cohort (n=349). After cross-validation using 5-fold iterative resampling, the algorithm was applied in a holdout sample of the cohort (n=150). The prevalence of FGS (ascertained by expert review) was 23.4% in the study population. The screening algorithm included childhood and travel exposure to rivers and streams; testing positive for visual inspection of the cervix with acetic acid; hematuria; reporting less than the median average age at sexual debut (<17 years); when asked what diseases can be transmitted via freshwater exposure, reporting ‘none’; being born outside of Lusaka or Copperbelt Province; and reporting occupation as ‘Housekeeper’. The screening algorithm had reasonable discrimination in the derivation cohort (area under the curve [AUC]=0.69, 95% confidence interval [CI]: 0.66-0.79, p-value<0.001). Using a score cut off ≥ 2 the risk algorithm in the derivation cohort had 77% sensitivity, 48% specificity, 35% positive predictive value, and 85% negative predictive value. Conclusions/Significance: Given the prevalence of FGS and associated morbidities, improved screening for FGS is imperative. We developed a simple screening algorithm to improve the diagnosis and treatment of FGS among adult women in Zambian government clinics. Copyright © 2024 Rogers, Mwangelwa, Kabengele, Kilembe, Vwalika, Inambao, Mumba, Chanda, Secor, Musale, Himukumbwa, Parker, Tichacek, Bougouma, Allen and Wall. |
Geographical distribution of Anopheles stephensi in eastern Ethiopia (preprint)
Balkew M , Mumba P , Dengela D , Yohannes G , Getachew D , Yared S , Chibsa S , Murphy M , George K , Lopez K , Janies D , Choi SH , Spear J , Irish SR , Carter TE . bioRxiv 2019 802587 Background The recent detection of the South Asian malaria vector An. stephensi in Ethiopia and other regions in the Horn of Africa has raised concerns about its potential impact on malaria transmission. We report here findings of survey for this species in eastern Ethiopia using both morphological and molecular methods for species identification.Methods Adult and larval/pupal collections were conducted at ten sites in eastern Ethiopia and Anopheles specimens’ species were determined using standard morphological keys and genetic analysis.Results In total, 2,231 morphologically identified An. stephensi were collected. A molecular approach incorporating both PCR endpoint assay and sequencing of portions of the internal transcribed spacer 2 (ITS2) and cytochrome oxidase I (COI) loci confirmed the identity of the An. stephensi in most cases (119/124 of the morphologically identified An. stephensi confirmed molecularly). Additionally, we observed Aedes aegypti larvae and pupae at many of the An. stephensi larval habitats.Conclusions Our findings show that An. stephensi is widely distributed in eastern Ethiopia and highlight the need for further surveillance in the southern, western and northern parts of the country and throughout the Horn of Africa. |
Progress toward Hepatitis B control and elimination of mother-to-child transmission of Hepatitis B virus - World Health Organization African Region, 2016-2021
Kabore HJ , Li X , Alleman MM , Manzengo CM , Mumba M , Biey J , Paluku G , Bwaka AM , Impouma B , Tohme RA . MMWR Morb Mortal Wkly Rep 2023 72 (29) 782-787 Chronic hepatitis B virus (HBV) infection is one of the leading causes of cirrhosis and liver cancer. In 2019, approximately 1.5 million persons newly acquired chronic HBV infection; among these, 990,000 (66%) were in the World Health Organization (WHO) African Region (AFR). Most chronic HBV infections are acquired through mother-to-child transmission (MTCT) or during early childhood, and approximately two thirds of these infections occur in AFR. In 2016, the World Health Assembly endorsed the goal of elimination of mother-to-child transmission (EMTCT) of HBV, documented by ≥90% coverage with both a timely hepatitis B vaccine (HepB) birth dose (HepB-BD) and 3 infant doses of HepB (HepB3), and ≤0.1% hepatitis B surface antigen (HBsAg) seroprevalence among children aged ≤5 years. In 2016, the WHO African Regional Committee endorsed targets for a 30% reduction in incidence (≤2% HBsAg seroprevalence in children aged ≤5 years) and ≥90% HepB3 coverage by 2020. By 2021, all 47 countries in the region provided HepB3 to infants beginning at age 6 weeks, and 14 countries (30%) provided HepB-BD. By December 2021, 16 (34%) countries achieved ≥90% HepB3 coverage, and only two (4%) achieved ≥90% timely HepB-BD coverage. Eight countries (17%) conducted nationwide serosurveys among children born after the introduction of HepB to assess HBsAg seroprevalence: six countries had achieved ≤2% seroprevalence, but none had achieved ≤0.1% seroprevalence among children. The development of immunization recovery plans following the COVID-19 pandemic provides an opportunity to accelerate progress toward hepatitis B control and EMTCT, including introducing HepB-BD and increasing coverage with timely HepB-BD and HepB3 vaccination. Representative HBsAg serosurveys among children and a regional verification body for EMTCT of HBV will be needed to monitor progress. |
Peer community health workers improve HIV testing and ART linkage among key populations in Zambia: retrospective observational results from the Z-CHECK project, 2019-2020.
Lindsay BR , Mwango L , Toeque MG , Malupande SL , Nkhuwa E , Moonga CN , Chilambe A , Sakala H , Kafunda I , Olowski P , Olufunso A , Okuku J , Kancheya N , Mumba D , Hachaambwa L , Sheneberger R , Blanco N , Lavoie MC , Claassen CW . J Int AIDS Soc 2022 25 (11) e26030 INTRODUCTION: Zambia has made tremendous progress towards HIV epidemic control; however, gaps remain among key populations (KPs), such as female sex workers (FSWs), men who have sex with men (MSM), people who inject drugs (PWID) and people in prisons and enclosed settings due to cultural, social and legal barriers. The University of Maryland, Baltimore Zambia Community HIV Epidemic Control for Key Populations (Z-CHECK) project aimed to improve HIV case-finding, linkage and treatment adherence at the community level for KPs in Zambia. We describe Z-CHECK strategies and examine HIV positivity yield and antiretroviral therapy (ART) linkage among KPs to inform ongoing programme improvement. METHODS: Z-CHECK recruited, trained and deployed peer community health workers (CHWs) for KP groups, with ongoing mentorship in community engagement. CHWs offered HIV testing in safe spaces and escorted newly HIV-diagnosed clients for same-day ART initiation. Z-CHECK also reached out to KP community leaders and gatekeepers for KP mobilization and trained healthcare workers (HCWs) on KP services and sensitivity. We conducted a retrospective observational review of routinely collected aggregate data for KPs aged ≥15 years at high risk for HIV transmission across five districts in Zambia from January 2019 to December 2020. RESULTS: Z-CHECK provided HIV testing for 9211 KPs, of whom 2227 were HIV positive (positivity yield, 24%). Among these, 1901 (85%) were linked to ART; linkage for MSM, FSW, PWID and people in prisons and enclosed settings was 95%, 89%, 86% and 65%, respectively. Programme strategies that contributed to high positivity yield and linkage included the use of peer KP CHWs, social network testing strategies and opportunities for same-day ART initiation. Challenges to programme implementation included stigma and discrimination among HCWs, as well as KP CHW attrition, which may be explained by high mobility. CONCLUSIONS: Peer CHWs were highly effective at reaching KP communities, identifying persons living with HIV and linking them to care. Engaging KP community gatekeepers resulted in high diffusion of health messages and increased access to health resources. The mobility of CHWs and HCWs is a challenge for programme implementation. Innovative interventions are needed to support PWID and people in prisons and enclosed settings. |
Reaching transgender populations in Zambia for HIV prevention and linkage to treatment using community-based service delivery
Mwango L , Toeque MG , Lindsay B , Tembo K , Sakala H , Reggee S , Malunga SM , Kabwe M , Kafunda I , Olufunso A , Mwila A , Okuku J , Kancheya N , Nkwemu K , Mumba D , Hachaambwa L , Sheneberger R , Blanco N , Lavoie MC , Stafford KA , Claassen CW . J Int AIDS Soc 2022 25 Suppl 5 e25995 INTRODUCTION: Transgender and gender-diverse communities in Zambia are highly vulnerable and experience healthcare differently than cisgender persons. The University of Maryland, Baltimore (UMB) supports projects in Zambia to improve HIV case-finding, linkage and antiretroviral treatment (ART) for Zambia's transgender community. We describe programme strategies and outcomes for HIV prevention, testing and ART linkage among transgender communities. METHODS: UMB utilizes a differentiated service delivery model whereby community health workers (CHWs) recruited from key populations (KPs) reach community members through a peer-to-peer approach, with the support of local transgender civil society organizations (CSOs) and community gatekeepers. Peer CHWs are trained and certified as HIV testers and psychosocial counsellors to offer counselling with HIV testing and prevention services in identified safe spaces. HIV-negative people at risk of HIV infection are offered pre-exposure prophylaxis (PrEP), while those who test positive for HIV are linked to ART services. CHWs collect data using the standardized facility and community tools and a dedicated DHIS2 database system. We conducted a descriptive analysis examining HIV testing and prevention outcomes using proportions and comparisons by time period and geographic strata. RESULTS: From October 2020 to June 2021, across Eastern, Lusaka, Western and Southern Provinces, 1860 transgender persons were reached with HIV prevention messages and services. Of these, 424 (23%) were tested for HIV and 78 (18%) tested positive. Of the 346 HIV-negative persons, 268 (78%) eligible transgender individuals were initiated on PrEP. ART linkage was 97%, with 76 out of the 78 transgender individuals living with HIV initiating treatment. Programme strategies that supported testing and linkage included peer CHWs, social network strategy testing, same-day ART initiation and local KP CSO support. Challenges included non-transgender-friendly environments, stigma and discrimination, the high transiency of the transgender community and the non-availability of transgender-specific health services, such as hormonal therapy. CONCLUSIONS: Peer KP CHWs were able to reach many members of the transgender community, providing safe HIV testing, PrEP services and linkage to care. Focusing on community gatekeepers and CSOs to disburse health messages and employ welcoming strategies supported high linkage to both PrEP and ART for transgender people in Zambia. |
An experimental hut study evaluating the impact of pyrethroid-only and PBO nets alone and in combination with pirimiphos-methyl-based IRS in Ethiopia
Yewhalaw D , Balkew M , Zemene E , Chibsa S , Mumba P , Flatley C , Seyoum A , Yoshimizu M , Zohdy S , Dengela D , Irish S . Malar J 2022 21 (1) 238 BACKGROUND: Pyrethroid resistance observed in populations of malaria vectors is widespread in Ethiopia and could potentially compromise the effectiveness of insecticide-based malaria vector control interventions. In this study, the impact of combining indoor residual spraying (IRS) and insecticide-treated nets (ITNs) on mosquito behaviour and mortality was evaluated using experimental huts. METHODS: A Latin Square Design was employed using six experimental huts to collect entomological data. Human volunteers slept in huts with different types of nets (pyrethroid-only net, PBO net, and untreated net) either with or without IRS (Actellic 300CS). The hut with no IRS and an untreated net served as a negative control. The study was conducted for a total of 54 nights. Both alive and dead mosquitoes were collected from inside nets, in the central rooms and verandah the following morning. Data were analysed using Stata/SE 14.0 software package (College Station, TX, USA). RESULTS: The personal protection rate of huts with PermaNet® 2.0 alone and PermaNet® 3.0 alone was 33.3% and 50%, respectively. The mean killing effect of huts with PermaNet® 2.0 alone and PermaNet® 3.0 alone was 2% and 49%, respectively. Huts with PermaNet® 2.0 alone and PermaNet® 3.0 alone demonstrated significantly higher excito-repellency than the control hut. However, mosquito mortality in the hut with IRS + untreated net, hut with IRS + PermaNet® 2.0 and hut with IRS + PermaNet® 3.0 were not significantly different from each other (p > 0.05). Additionally, pre-exposure of both the susceptible Anopheles arabiensis laboratory strain and wild Anopheles gambiae sensu lato to PBO in the cone bioassay tests of Actellic 300CS sprayed surfaces did not reduce mosquito mortality when compared to mortality without pre-exposure to PBO. CONCLUSION: Mosquito mortality rates from the huts with IRS alone were similar to mosquito mortality rates from the huts with the combination of vector control intervention tools (IRS + ITNs) and mosquito mortality rates from huts with PBO nets alone were significantly higher than huts with pyrethroid-only nets. The findings of this study help inform studies to be conducted under field condition for decision-making for future selection of cost-effective vector control intervention tools. |
Detection and population genetic analysis of kdr L1014F variant in eastern Ethiopian Anopheles stephensi.
Samake JN , Yared S , Getachew D , Mumba P , Dengela D , Yohannes G , Chibsa S , Choi SH , Spear J , Irish SR , Zohdy S , Balkew M , Carter TE . Infect Genet Evol 2022 99 105235 ![]() ![]() Anopheles stephensi is a malaria vector that has been recently introduced into East Africa, where it threatens to increase malaria disease burden. The use of insecticides, especially pyrethroids, is still one of the primary malaria vector control strategies worldwide. The knockdown resistance (kdr) mutation in the IIS6 transmembrane segment of the voltage-gated sodium channel (vgsc) is one of the main molecular mechanisms of pyrethroid resistance in Anopheles. Extensive pyrethroid resistance in An. stephensi has been previously reported in Ethiopia. Thus, it is important to determine whether or not the kdr mutation is present in An. stephensi populations in Ethiopia to inform vector control strategies. In the present study, the kdr locus was analyzed in An. stephensi collected from ten urban sites (Awash Sebat Kilo, Bati, Dire Dawa, Degehabur, Erer Gota, Godey, Gewane, Jigjiga, Semera, and Kebridehar) situated in Somali, Afar, and Amhara regions, and Dire Dawa Administrative City, to evaluate the frequency and evolution of kdr mutations and the association of the mutation with permethrin resistance phenotypes. Permethrin is one of the pyrethroid insecticides used for vector control in eastern Ethiopia. DNA extractions were performed on adult mosquitoes from CDC light trap collections and those raised from larval and pupal collections. PCR and targeted sequencing were used to analyze the IIS6 transmembrane segment of the vgsc gene. Of 159 An. stephensi specimens analyzed from the population survey, nine (5.7%) carried the kdr mutation (L1014F). An. stephensi with kdr mutations were only observed from Bati, Degehabur, Dire Dawa, Gewane, and Semera. We further randomly selected twenty resistant and twenty susceptible An. stephensi mosquitoes from Dire Dawa post-exposure to permethrin and investigated the role of kdr in pyrethroid resistance by comparing the vgsc gene in the two populations. We found no kdr mutations in the permethrin-resistant mosquitoes. Population genetic analysis of the sequences, including neighboring introns, revealed limited evidence of non-neutral evolution (e.g., selection) at this locus. The low kdr mutation frequency detected and the lack of kdr mutation in the permethrin-resistant mosquitoes suggest the existence of other molecular mechanisms of pyrethroid resistance in eastern Ethiopian An. stephensi. |
Genetic diversity of Anopheles stephensi in Ethiopia provides insight into patterns of spread.
Carter TE , Yared S , Getachew D , Spear J , Choi SH , Samake JN , Mumba P , Dengela D , Yohannes G , Chibsa S , Murphy M , Dissanayake G , Flately C , Lopez K , Janies D , Zohdy S , Irish SR , Balkew M . Parasit Vectors 2021 14 (1) 602 ![]() ![]() BACKGROUND: The recent detection of the South Asian malaria vector Anopheles stephensi in the Horn of Africa (HOA) raises concerns about the impact of this mosquito on malaria transmission in the region. Analysis of An. stephensi genetic diversity and population structure can provide insight into the history of the mosquito in the HOA to improve predictions of future spread. We investigated the genetic diversity of An. stephensi in eastern Ethiopia, where detection suggests a range expansion into this region, in order to understand the history of this invasive population. METHODS: We sequenced the cytochrome oxidase subunit I (COI) and cytochrome B gene (CytB) in 187 An. stephensi collected from 10 sites in Ethiopia in 2018. Population genetic, phylogenetic, and minimum spanning network analyses were conducted for Ethiopian sequences. Molecular identification of blood meal sources was also performed using universal vertebrate CytB sequencing. RESULTS: Six An. stephensi COI-CytB haplotypes were observed, with the highest number of haplotypes in the northeastern sites (Semera, Bati, and Gewana towns) relative to the southeastern sites (Kebridehar, Godey, and Degehabur) in eastern Ethiopia. We observed population differentiation, with the highest differentiation between the northeastern sites compared to central sites (Erer Gota, Dire Dawa, and Awash Sebat Kilo) and the southeastern sites. Phylogenetic and network analysis revealed that the HOA An. stephensi are more genetically similar to An. stephensi from southern Asia than from the Arabian Peninsula. Finally, molecular blood meal analysis revealed evidence of feeding on cows, goats, dogs, and humans, as well as evidence of multiple (mixed) blood meals. CONCLUSION: We show that An. stephensi is genetically diverse in Ethiopia and with evidence of geographical structure. Variation in the level of diversity supports the hypothesis for a more recent introduction of An. stephensi into southeastern Ethiopia relative to the northeastern region. We also find evidence that supports the hypothesis that HOA An. stephensi populations originate from South Asia rather than the Arabian Peninsula. The evidence of both zoophagic and anthropophagic feeding support the need for additional investigation into the potential for livestock movement to play a role in vector spread in this region. |
Initial implementation of PrEP in Zambia: health policy development and service delivery scale-up
Claassen CW , Mumba D , Njelesani M , Nyimbili D , Mwango LK , Mwitumwa M , Mubanga E , Mulenga LB , Chisenga T , Nichols BE , Hendrickson C , Chitembo L , Okuku J , O'Bra H . BMJ Open 2021 11 (7) e047017 INTRODUCTION: Daily pre-exposure prophylaxis (PrEP) for HIV prevention is highly effective, but not yet widely deployed in sub-Saharan Africa. We describe how Zambia developed PrEP health policy and then successfully implemented national PrEP service delivery. POLICY DEVELOPMENT: Zambia introduced PrEP as a key strategy for HIV prevention in 2016, and established a National PrEP Task Force to lead policy advocacy and development. The Task Force was composed of government representatives, regulatory agencies, international donors, implementation partners and civil society organisations. Following an implementation pilot, PrEP was rolled out nationally using risk-based criteria alongside a national HIV prevention campaign. NATIONAL SCALE-UP: In the first year of implementation, ending September 2018, 3626 persons initiated PrEP. By September 2019, the number of people starting PrEP increased by over sixfold to 23 327 persons at 728 sites across all ten Zambian provinces. In the first 2 years, 26 953 clients initiated PrEP in Zambia, of whom 31% were from key and priority populations. Continuation remains low at 25% and 11% at 6 and 12 months, respectively. LESSONS LEARNT: Risk-based criteria for PrEP ensures access to those most in need of HIV prevention. Healthcare worker training in PrEP service delivery and health needs of key and priority populations is crucial. PrEP expansion into primary healthcare clinics and community education is required to reach full potential. Additional work is needed to understand and address low PrEP continuation. Finally, a task force of key stakeholders can rapidly develop and implement health policy, which may serve as a model for countries seeking to implement PrEP. |
An update on the distribution, bionomics, and insecticide susceptibility of Anopheles stephensi in Ethiopia, 2018-2020
Balkew M , Mumba P , Yohannes G , Abiy E , Getachew D , Yared S , Worku A , Gebresilassie A , Tadesse FG , Gadisa E , Esayas E , Ashine T , Yewhalaw D , Chibsa S , Teka H , Murphy M , Yoshimizu M , Dengela D , Zohdy S , Irish S . Malar J 2021 20 (1) 263 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. |
Anopheles stephensi Mosquitoes as Vectors of Plasmodium vivax and falciparum, Horn of Africa, 2019
Tadesse FG , Ashine T , Teka H , Esayas E , Messenger LA , Chali W , Meerstein-Kessel L , Walker T , Wolde Behaksra S , Lanke K , Heutink R , Jeffries CL , Mekonnen DA , Hailemeskel E , Tebeje SK , Tafesse T , Gashaw A , Tsegaye T , Emiru T , Simon K , Bogale EA , Yohannes G , Kedir S , Shumie G , Sabir SA , Mumba P , Dengela D , Kolaczinski JH , Wilson A , Churcher TS , Chibsa S , Murphy M , Balkew M , Irish S , Drakeley C , Gadisa E , Bousema T . Emerg Infect Dis 2021 27 (2) 603-607 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. |
Increase in antiretroviral therapy enrollment among persons with HIV infection during the Lusaka HIV treatment surge - Lusaka Province, Zambia, January 2018-June 2019
Boyd MA , Shah M , Barradas DT , Herce M , Mulenga LB , Lumpa M , Ishimbulo S , Saadani A , Mumba M , Essiet-Gibson I , Tally L , Minchella P , Kancheya N , Mwila A , Zyambo K , Chungu C , Chanda S , Mbewe W , Zulu I , Siansalama T , Mweebo K , Nkwemu K , Simpungwe J , Medley A , Sikazwe I , Mwale C , Agolory S , Ellerbrock T . MMWR Morb Mortal Wkly Rep 2020 69 (31) 1039-1043 Within Zambia, a landlocked country in southern-central Africa, the highest prevalence of human immunodeficiency virus (HIV) infection is in Lusaka Province (population 3.2 million), where approximately 340,000 persons are estimated to be infected (1). The 2016 Zambia Population-based HIV Impact Assessment (ZAMPHIA) estimated the adult HIV prevalence in Lusaka Province to be 15.7%, with a 62.7% viral load suppression rate (HIV-1 RNA <1,000 copies/mL) (2). ZAMPHIA results highlighted remaining treatment gaps in Zambia overall and by subpopulation. In January 2018, Zambia launched the Lusaka Province HIV Treatment Surge (Surge project) to increase enrollment of persons with HIV infection onto antiretroviral therapy (ART). The Zambia Ministry of Health (MoH), CDC, and partners analyzed the U.S. President's Emergency Plan for AIDS Relief (PEPFAR) Monitoring and Evaluation Reporting data set to assess the effectiveness of the first 18 months of the Surge project (January 2018-June 2019). During this period, approximately 100,000 persons with positive test results for HIV began ART. These new ART clients were more likely to be persons aged 15-24 years. In addition, the number of persons with documented viral load suppression doubled from 66,109 to 134,046. Lessons learned from the Surge project, including collaborative leadership, efforts to improve facility-level performance, and innovative strategies to disseminate successful practices, could increase HIV treatment rates in other high-prevalence settings. |
Geographical distribution of Anopheles stephensi in eastern Ethiopia.
Balkew M , Mumba P , Dengela D , Yohannes G , Getachew D , Yared S , Chibsa S , Murphy M , George K , Lopez K , Janies D , Choi SH , Spear J , Irish SR , Carter TE . Parasit Vectors 2020 13 (1) 35 ![]() BACKGROUND: The recent detection of the South Asian malaria vector Anopheles stephensi in Ethiopia and other regions in the Horn of Africa has raised concerns about its potential impact on malaria transmission. We report here the findings of a survey for this species in eastern Ethiopia using both morphological and molecular methods for species identification. METHODS: Adult and larval/pupal collections were conducted at ten sites in eastern Ethiopia and Anopheles specimens were identified using standard morphological keys and genetic analysis. RESULTS: In total, 2231 morphologically identified An. stephensi were collected. A molecular approach incorporating both PCR endpoint assay and sequencing of portions of the internal transcribed spacer 2 (ITS2) and cytochrome c oxidase subunit 1 (cox1) loci confirmed the identity of the An. stephensi in most cases (119/124 of the morphologically identified An. stephensi confirmed molecularly). Additionally, we observed Aedes aegypti larvae and pupae at many of the An. stephensi larval habitats. CONCLUSIONS: Our findings show that An. stephensi is widely distributed in eastern Ethiopia and highlight the need for further surveillance in the southern, western and northern parts of the country and throughout the Horn of Africa. |
Impact of the Saving Mothers, Giving Life approach on decreasing maternal and perinatal deaths in Uganda and Zambia
Serbanescu F , Clark TA , Goodwin MM , Nelson LJ , Boyd MA , Kekitiinwa AR , Kaharuza F , Picho B , Morof D , Blanton C , Mumba M , Komakech P , Carlosama F , Schmitz MM , Conlon CM . Glob Health Sci Pract 2019 7 S27-s47 BACKGROUND: Maternal and perinatal mortality is a global development priority that continues to present major challenges in sub-Saharan Africa. Saving Mothers, Giving Life (SMGL) was a multipartner initiative implemented from 2012 to 2017 with the goal of improving maternal and perinatal health in high-mortality settings. The initiative accomplished this by reducing delays to timely and appropriate obstetric care through the introduction and support of community and facility evidence-based and district-wide health systems strengthening interventions. METHODS: SMGL-designated pilot districts in Uganda and Zambia documented baseline and endline maternal and perinatal health outcomes using multiple approaches. These included health facility assessments, pregnancy outcome monitoring, enhanced maternal mortality detection in facilities, and district population-based identification and investigation of maternal deaths in communities. RESULTS: Over the course of the 5-year SMGL initiative, population-based estimates documented a 44% reduction in the SMGL-supported district-wide maternal mortality ratio (MMR) in Uganda (from 452 to 255 maternal deaths per 100,000 live births) and a 41% reduction in Zambia (from 480 to 284 maternal deaths per 100,000 live births). The MMR in SMGL-supported health facilities declined by 44% in Uganda and by 38% in Zambia. The institutional delivery rate increased by 47% in Uganda (from 45.5% to 66.8% of district births) and by 44% in Zambia (from 62.6% to 90.2% of district births). The number of facilities providing emergency obstetric and newborn care (EmONC) rose from 10 to 26 in Uganda and from 7 to 13 in Zambia, and lower- and mid-level facilities increased the number of EmONC signal functions performed. Cesarean delivery rates increased by more than 70% in both countries, reaching 9% and 5% of all births in Uganda and Zambia districts, respectively. Maternal deaths in facilities due to obstetric hemorrhage declined by 42% in Uganda and 65% in Zambia. Overall, perinatal mortality rates declined, largely due to reductions in stillbirths in both countries; however, no statistically significant changes were found in predischarge neonatal death rates in predischarge either country. CONCLUSIONS: MMRs fell significantly in Uganda and Zambia following the introduction of the SMGL interventions, and SMGL's comprehensive district systems-strengthening approach successfully improved coverage and quality of care for mothers and newborns. The lessons learned from the initiative can inform policy makers and program managers in other low- and middle-income settings where similar approaches could be used to rapidly reduce preventable maternal and newborn deaths. |
Scale-up of voluntary medical male circumcision services for HIV prevention - 12 countries in southern and eastern Africa, 2013-2016
Hines JZ , Ntsuape OC , Malaba K , Zegeye T , Serrem K , Odoyo-June E , Nyirenda RK , Msungama W , Nkanaunena K , Come J , Canda M , Nhaguiombe H , Shihepo EK , Zemburuka BLT , Mutandi G , Yoboka E , Mbayiha AH , Maringa H , Bere A , Lawrence JJ , Lija GJI , Simbeye D , Kazaura K , Mwiru RS , Talisuna SA , Lubwama J , Kabuye G , Zulu JE , Chituwo O , Mumba M , Xaba S , Mandisarisa J , Baack BN , Hinkle L , Grund JM , Davis SM , Toledo C . MMWR Morb Mortal Wkly Rep 2017 66 (47) 1285-1290 Countries in Southern and Eastern Africa have the highest prevalence of human immunodeficiency virus (HIV) infection in the world; in 2015, 52% (approximately 19 million) of all persons living with HIV infection resided in these two regions.* Voluntary medical male circumcision (VMMC) reduces the risk for heterosexually acquired HIV infection among males by approximately 60% (1). As such, it is an essential component of the Joint United Nations Programme on HIV/AIDS (UNAIDS) strategy for ending acquired immunodeficiency syndrome (AIDS) by 2030 (2). Substantial progress toward achieving VMMC targets has been made in the 10 years since the World Health Organization (WHO) and UNAIDS recommended scale-up of VMMC for HIV prevention in 14 Southern and Eastern African countries with generalized HIV epidemics and low male circumcision prevalence (3).(dagger) This has been enabled in part by nearly $2 billion in cumulative funding through the President's Emergency Plan for AIDS Relief (PEPFAR), administered through multiple U.S. governmental agencies, including CDC, which has supported nearly half of all PEPFAR-supported VMMCs to date. Approximately 14.5 million VMMCs were performed globally during 2008-2016, which represented 70% of the original target of 20.8 million VMMCs in males aged 15-49 years through 2016 (4). Despite falling short of the target, these VMMCs are projected to avert 500,000 HIV infections by the end of 2030 (4). However, UNAIDS has estimated an additional 27 million VMMCs need to be performed by 2021 to meet the Fast Track targets (2). This report updates a previous report covering the period 2010-2012, when VMMC implementing partners supported by CDC performed approximately 1 million VMMCs in nine countries (5). During 2013-2016, these implementing partners performed nearly 5 million VMMCs in 12 countries. Meeting the global target will require redoubling current efforts and introducing novel strategies that increase demand among subgroups of males who have historically been reluctant to undergo VMMC. |
Implementation of rotavirus surveillance and vaccine introduction - World Health Organization African Region, 2007-2016
Mwenda JM , Burke RM , Shaba K , Mihigo R , Tevi-Benissan MC , Mumba M , Biey JN , Cheikh D , Poy MSc A , Zawaira FR , Aliabadi N , Tate JE , Hyde T , Cohen AL , Parashar UD . MMWR Morb Mortal Wkly Rep 2017 66 (43) 1192-1196 Rotavirus is a leading cause of severe pediatric diarrhea globally, estimated to have caused 120,000 deaths among children aged <5 years in sub-Saharan Africa in 2013 (1). In 2009, the World Health Organization (WHO) recommended rotavirus vaccination for all infants worldwide (2). Two rotavirus vaccines are currently licensed globally: the monovalent Rotarix vaccine (RV1, GlaxoSmithKline; 2-dose series) and the pentavalent RotaTeq vaccine (RV5, Merck; 3-dose series). This report describes progress of rotavirus vaccine introduction (3), coverage (using estimates from WHO and the United Nations Children's Fund [UNICEF]) (4), and impact on pediatric diarrhea hospitalizations in the WHO African Region. By December 2016, 31 (66%) of 47 countries in the WHO African Region had introduced rotavirus vaccine, including 26 that introduced RV1 and five that introduced RV5. Among these countries, rotavirus vaccination coverage (completed series) was 77%, according to WHO/UNICEF population-weighted estimates. In 12 countries with surveillance data available before and after vaccine introduction, the proportion of pediatric diarrhea hospitalizations that were rotavirus-positive declined 33%, from 39% preintroduction to 26% following rotavirus vaccine introduction. These results support introduction of rotavirus vaccine in the remaining countries in the region and continuation of rotavirus surveillance to monitor impact. |
Knowledge and attitude towards Ebola and Marburg virus diseases in Uganda using quantitative and participatory epidemiology techniques
Nyakarahuka L , Skjerve E , Nabadda D , Sitali DC , Mumba C , Mwiine FN , Lutwama JJ , Balinandi S , Shoemaker T , Kankya C . PLoS Negl Trop Dis 2017 11 (9) e0005907 BACKGROUND: Uganda has reported five (5) Ebola virus disease outbreaks and three (3) Marburg virus disease outbreaks from 2000 to 2016. Peoples' knowledge and attitude towards Ebola and Marburg virus disease impact on control and prevention measures especially during outbreaks. We describe knowledge and attitude towards Ebola and Marburg virus outbreaks in two affected communities in Uganda to inform future outbreak responses and help in the design of health education and communication messages. METHODS: The study was a community survey done in Luweero, Ibanda and Kamwenge districts that have experienced outbreaks of Ebola and Marburg virus diseases. Quantitative data were collected using a structured questionnaire and triangulated with qualitative participatory epidemiology techniques to gain a communities' knowledge and attitude towards Ebola and Marburg virus disease. RESULTS: Out of 740 respondents, 48.5% (359/740) were categorized as being knowledgeable about Ebola and Marburg virus diseases, whereas 60.5% (448/740) were having a positive attitude towards control and prevention of Ebola and Marburg virus diseases. The mean knowledge and attitude percentage scores were 54.3 (SD = 23.5, 95%CI = 52.6-56.0) and 69.9 (SD = 16.9, 95%CI = 68.9-71.1) respectively. People educated beyond primary school were more likely to be knowledgeable about Ebola and Marburg virus disease than those who did not attain any formal education (OR = 3.6, 95%CI = 2.1-6.1). Qualitative data revealed that communities describe Ebola and Marburg virus diseases as very severe diseases with no cure and they believe the diseases spread so fast. Respondents reported fear and stigma suffered by survivors, their families and the broader community due to these diseases. CONCLUSION: Communities in Uganda affected by filovirus outbreaks have moderate knowledge about these diseases and have a positive attitude towards practices to prevent and control Ebola and Marburg viral diseases. The public health sector should enhance this community knowledge gap to empower them more by supplying educational materials for epidemic preparedness in future using appropriate communication channels as proposed by the communities. |
A reduction in malaria transmission intensity in Northern Ghana after 7 years of indoor residual spraying
Coleman S , Dadzie SK , Seyoum A , Yihdego Y , Mumba P , Dengela D , Ricks P , George K , Fornadel C , Szumlas D , Psychas P , Williams J , Appawu MA , Boakye DA . Malar J 2017 16 (1) 324 BACKGROUND: Indoor residual spraying (IRS) is being implemented as one of the malaria prevention methods in the Northern Region of Ghana. Changes in longevity, sporozoite and entomological inoculation rates (EIRs) of major malaria vectors were monitored to assess the impact of IRS in selected districts. METHODS: Monthly human landing catches (HLCs) were used to collect mosquitoes from sentinel sites in three adjacent districts between July 2009 and December 2014: Savelugu Nanton (SND) where IRS had been implemented from 2008 to 2014; Tolon Kumbungu (TKD) where IRS had been implemented between 2008 and 2012 and Tamale Metropolis (TML) with no history of IRS. Mosquitoes were morphologically identified to species level and into sibling species, using PCR. Samples of Anopheles gambiae sensu lato (s.l.) were examined for parity and infectivity. EIR was calculated from biting and infectivity rates of malaria vectors. RESULTS: Parity rates of An. gambiae s.l. decreased significantly (p < 0.0001) in SND from 44.8% in 2011 to 28.1% by 2014, and in TKD from 53.3% in 2011 to 46.6% in 2012 (p = 0.001). However 2 years after IRS was discontinued in TKD, the proportion of parous An. gambiae s.l. increased significantly to 68.5% in 2014 (p < 0.0001). Parity rates in the unsprayed district remained high throughout the study period, ranging between 68.6% in 2011 and 72.3% in 2014. The sum of monthly EIRs post-IRS season (July-December) in SND ranged between 2.1 and 6.3 infective bites/person/season (ib/p/s) during the 3 years that the district was sprayed with alphacypermethrin. EIR in SND was reduced to undetectable levels when the insecticide was switched to pirimiphos methyl CS in 2013 and 2014. Two years after IRS was withdrawn from TKD the sum of monthly EIRs (July-December) increased by about fourfold from 41.8 ib/p/s in 2012 to 154.4 ib/p/s in 2014. The EIR in the control area, TML, ranged between 35 ib/p/s in 2009 to 104.71 ib/p/s by 2014. CONCLUSIONS: This study demonstrates that IRS application did have a significant impact on entomological indicators of malaria transmission in the IRS project districts of Northern Ghana. Transmission indicators increased following the withdrawal of IRS from Tolon Kumbungu District. |
Hepatitis B virus infection among HIV-infected pregnant women in Malawi and transmission to infants
Chasela CS , Kourtis AP , Wall P , Drobeniuc J , King CC , Thai H , Teshale EH , Hosseinipour M , Ellington S , Codd MB , Jamieson DJ , Knight R , Fitzpatrick P , Kamili S , Hoffman I , Kayira D , Mumba N , Kamwendo DD , Martinson F , Powderly W , Teo CG , van der Horst C . J Hepatol 2014 60 (3) 508-14 BACKGROUND & AIMS: The extent of HBV infection to infants of HBV/HIV-coinfected pregnant women in sub-Saharan Africa is unknown. The aim of this study was to assess prevalence of HBV infection among antiretroviral-naive, HIV-infected pregnant women in Malawi and examine HBV transmission to their infants. METHODS: Plasma from 2048 HIV-infected, Malawian women and their infants were tested for markers of HBV infection. Study participants were provided standard-of-care health services, which included administration of pentavalent vaccine to infants at 6, 10, and 14weeks of age. RESULTS: One-hundred and three women (5%) were HBsAg-positive; 70 of these HBsAg-positive women were also HBV-DNA-positive. Sixteen women (0.8%) were HBV-DNA-positive but HBsAg-negative. Five of 51 infants (9.8%) born to HBsAg-positive and/or HBV-DNA-positive women were HBV-DNA-positive by 48weeks of age.HBV DNA concentrations of two infants of mothers who received extended lamivudine-containing anti-HIV prophylaxis were <4 log10 IU/ml compared to 8 log10 IU/ml in three infants of mothers who did not. CONCLUSIONS: HBV DNA was detected in nearly 10% of infants born to HBV/HIV-coinfected women. Antenatal testing for HIV and HBV, if instituted, can facilitate implementation of prophylactic measures against infant infection by both viruses. |
Prevalence of hepatitis C virus infection among human immunodeficiency virus-1-infected pregnant women in Malawi: the BAN study
Chasela CS , Wall P , Drobeniuc J , King CC , Teshale E , Hosseinipour MC , Ellington SR , Codd M , Jamieson DJ , Knight RJ , Fitzpatrick P , Kourtis AP , Hoffman IF , Kayira D , Mumba N , Kamwendo DD , Martinson F , Powderly W , van der Horst C , Kamili S . J Clin Virol 2012 54 (4) 318-320 ![]() BACKGROUND: In Sub-Saharan Africa, prevalence estimates of hepatitis C virus (HCV) vary widely. OBJECTIVES: To assess the prevalence of HCV infection among HIV-infected, pregnant women screened for a large clinical trial in Lilongwe, Malawi. STUDY DESIGN: Plasma from 2041 HIV-infected, pregnant women was screened for anti-HCV IgG using a chemiluminiscent immunometric assay (CIA). Specimens with a signal-cut-off ratio≥1.00 were considered reactive and those with S/Co ratio<1.00 non-reactive. All CIA-reactive specimens were tested by a recombinant immunoblot assay (RIBA) for anti-HCV and by PCR for HCV RNA. RESULTS: Of 2041 specimens, 110 (5.3%, 95% CI: 4.5-6.5%) were CIA reactive. Of the 109 CIA reactive specimens available for RIBA testing, 2 (1.8%) were positive, 28 (25.7%) were indeterminate, and 79 (72.5%) were negative. All CIA-reactive specimens were HCV RNA negative (n=110). The estimated HCV prevalence based on the screening assay alone was 5.3%; based on supplemental RIBA testing, the status of HCV infection remained indeterminate in 1.4% (28/2040, 95% CI: 0.1-2.0) and the prevalence of confirmed HCV infections was 0.1% (2/2040, 95% CI: 0-0.4%). CONCLUSIONS: HCV seroprevalence among HIV-infected, pregnant women in Malawi confirmed by supplemental RIBA HCV 3.0 is low (0.1%); CIA showed a high false-reactivity rate in this population. |
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