Biology subjects

Abubakar, A.

Publications and source records attributed to Abubakar, A..

3 recordsLinked to original sources

bioRxiv2025

Impact of Environmental Variables on the Seasonal Dynamics and Relative Abundance of Endosymbionts in Glossina Species in Northern Nigeria

This study explores how environmental factors influence the seasonal patterns and endosymbiont abundance in Glossina species across four ecological zones in northern Nigeria. Tsetse flies--the vectors of African trypanosomiasis--host both obligate and facultative endosymbionts, including Wigglesworthia glossinidia, Sodalis glossinidius, and Wolbachia pipientis, which affect their physiology and vector capacity. Over two years, 7,632 tsetse flies were collected and examined for species distribution, symbiont prevalence, and local climate variables (temperature, humidity, and vegetation index). Glossina tachinoides was most prevalent (55.78%), followed by G. morsitans submorsitans (29.36%) and G. palpalis palpalis (14.86%), each showing site-specific distribution. Endosymbiont prevalence rose markedly during the wet season (e.g., Yankari: 73.41% to 94.83%, p < 0.0001), especially for Sodalis, which declined under dry conditions. Strong negative correlations with temperature (r = -0.99, p = 0.0001) and positive correlations with humidity (r = +0.99, p = 0.0005) were observed. These patterns reflect the vulnerability of tsetse-symbiont systems to climate stress and underscore challenges for control strategies. Broad-area methods may suit G. tachinoides, while targeted trapping is more suitable for G. palpalis. The resilience of Wolbachia suggests its utility for paratransgenic control. The study emphasizes the importance of integrated, climate-aware surveillance and intervention strategies to mitigate trypanosomiasis risk. Author SummaryTsetse flies transmit African trypanosomiasis, a disease affecting livestock and rural livelihoods in sub-Saharan Africa. These flies harbor bacterial endosymbionts that influence their biology and vector competence. This study investigated how seasonal changes in temperature, humidity, and vegetation affect the abundance of tsetse flies and their symbionts in northern Nigeria. We found that certain symbionts, especially Sodalis glossinidius, decline sharply during hot-dry periods, while Wolbachia remains stable. Our findings highlight the need for adaptive, climate-informed vector control strategies and provide insights for integrating microbial monitoring into trypanosomiasis surveillance systems.

molecular biology↗

bioRxiv2023

An unusual two-strain cholera outbreak in Lebanon, 2022-2023: a genomic epidemiology study

BackgroundCholera is a bacterial infection caused by the ingestion of contaminated water or food. It principally affects the gastrointestinal system and spreads easily, causing outbreaks. The first case of cholera in this outbreak was detected in Lebanon in October 2022. The outbreak lasted three months, with 8,007 suspected cases (671 laboratory-confirmed) and 23 deaths. We characterised the Vibrio cholerae strain responsible for this cholera outbreak. MethodsIn total, 34 Vibrio cholerae isolates collected by random sampling of stools, water and plant samples throughout the outbreak and over the affected regions were studied by phenotypic methods and microbial genomics. FindingsAll isolates were V. cholerae O1, serotype Ogawa strains from wave 3 of the seventh pandemic El Tor (7PET) lineage. Phylogenomic analysis unexpectedly revealed the presence of two different 7PET strains, a highly unusual finding outside the Bay of Bengal, where several sublineages circulate together. The dominant strain had a narrow antibiotic resistance profile and was phylogenetically related to South Asian V. cholerae isolates. The second strain, which was found exclusively in South Lebanon and Beqaa, was resistant to multiple antibiotics, including macrolides, third-generation cephalosporins and cotrimoxazole. It belonged to the AFR13 sublineage and clustered with V. cholerae isolates collected in Yemen from 2016 to 2019. This second Lebanese strain also harboured the same multidrug-resistance (MDR) IncC-type plasmid found in Yemeni isolates from 2018. InterpretationThe 2022-2023 Lebanese cholera outbreak was caused by the simultaneous introduction of two different 7PET strains. The MDR strain was geographically limited, but the spread of this clone or the horizontal transfer of the MDR plasmid to more susceptible clones could affect epidemic cholera case management. Genomic surveillance is crucial to prevent further spread, and to ensure a prompt and effective response to outbreaks. FundingThe study was funded by the Centers for Disease Control (CDC) award number BAA 75D301-21-C-12132, a grant awarded to the American University of Beirut, WHO country office Lebanon, the Lebanese University, and Institut Pasteur. RESEARCH IN CONTEXT PANELO_ST_ABSEvidence before this studyC_ST_ABSWhole-genome sequencing (WGS) has greatly advanced our understanding and the characterisation of Vibrio cholerae outbreaks. However, few studies in the Middle East and North Africa (MENA) region have used this powerful technology. We searched PubMed for studies investigating the molecular epidemiology of V. cholerae by WGS in the MENA region, including Lebanon, with the terms "cholera*" AND "a country name of MENA countries" with no restrictions on language or date. The very small number of studies identified concerned Yemen and Algeria. All the outbreaks in the MENA region investigated to date and many others worldwide were caused by a single strain introduced once, contrasting with the endemic setting (the Bay of Bengal) in which several lineages circulate together. One manuscript addressing the history of cholera in Africa from a genomic perspective assigned three Lebanese strains from past outbreaks in 1970 and 1993 as O1 Ogawa isolates from waves 1 and 2 of the seventh pandemic lineage (7PET). Added value of the studyWe provide the first comprehensive overview of the molecular epidemiology of the V. cholerae strains responsible for the 2022-2023 Lebanese cholera outbreak. The use of WGS made it possible to distinguish clearly between two phylogenetically distant strains from genomic wave 3 of the 7PET lineage responsible for the Lebanese outbreak and to assign their putative origins to South Asia and Yemen. Based on their different susceptibility patterns (a predominant strain with a narrow resistance profile and a minor strain with an extended resistance profile), WGS excluded the hypothesis of the multidrug-resistant (MDR) minor strain emerging from the susceptible dominant strain through the acquisition of the MDR plasmid, instead clearly demonstrating the seeding of the outbreak by two different introductions. Implications of all available evidenceThis study demonstrates the importance of WGS associated with national surveillance for obtaining new insights and perspectives, modifying our perception of V. cholerae outbreak. This unexpected occurrence of a two-strain outbreak in a setting considered non-endemic for V. cholerae requires tight control by the local health authorities to prevent the sporadic introduction and spread of additional strains. Our findings raise the question of the extent to which the strains identified, particularly those from South Asia, spread in Iraq and Syria, neighbouring countries that declared cholera outbreaks before Lebanon. It is difficult to answer this question due to the lack of strains collected from these countries. Regional surveillance of the causal agent of cholera is therefore essential, to unravel transmission events and monitor the emergence of antimicrobial drug-resistant strains observed in many countries around the world.

microbiology↗

bioRxiv2019

Seroprevalence of Foot and Mouth Disease Virus Infection in some Wildlife and Cattle in Bauchi State, Nigeria

BackgroundFoot and mouth disease (FMD) is one of the most economically important transboundary animal diseases with devastating consequence on livestock production and wildlife conservation. The objectives of the study were: to determine the seroprevalence of FMDV in wildlife and cattle and identify circulating FMDV serotypes in wildlife and identify potential risk factors that will contribute to transmission of the disease at the wildlife-livestock interface in Yankari Game Reserve and Sumu Wildlife Park in Bauchi State, Nigeria.\n\nMethodsBlood samples were collected between 2013 to 2015 from some wildlife and cattle respectively within and around Yankari Game Reserve (YGR) and Sumu Wildlife Park (SWP) in Bauchi State, Nigeria. The Wild animals were immobilized for blood collection using a combination of Etorphine Hydrochloride (M99(R) Kruger-Med South Africa) at 0.5-2 mg/kg and Azaperone (Stresnil(R), Janssen Pharmaceuticals (Pty.) Ltd., South Africa) at 0.1 mg/kg using a Dan-Inject(R) rifle (Dan-Inject APS, Sellerup Skovvej, Denmark) fitted with 3 ml dart syringe and for reversal, Naltrexone (Trexonil(R) Kruger-Med South Africa) at 1.5 mg IM was used, cattle were restrained by the owners for blood collection. Harvested Sera from blood were screened for presence of Antibodies against FMDV using prioCHECK(R) 3 ABC NSP ELISA kit and positive samples from wildlife were serotyped using Solid-Phase Competitive ELISA, (IZSLER Brescia-Italy). Data obtained were analysed using Graphpad Prism version 7.\n\nResultsThe results showed that 197 (65.7%) of the 300 serum samples from cattle and 13 (24.5%) of the 53 serum samples from wildlife tested positive for antibodies to the highly conserved non-structural 3-ABC protein of FMDV and statistically significant (P <0.05). Classification of cattle into breed and sex showed that detectable antibodies to FMDV were higher (P <0.05) in White Fulani 157 (72.8%) than red Bororo 23 (39.7%) and Sokoto Gudali 17 (33.3%) breeds of cattle whereas in females detectable FMDV antibodies were higher (P <0.05) 150 (72.8%) than in males 47 (50.0%). In the wildlife species, antibodies to FMDV were detected in waterbuck 2 (28.6%), elephant 1 (25.0%), wildebeest 4 (33.3%) and eland 6 (25.0%). Four serotypes of FMDV: O, A, SAT-1 and SAT-2 were detected from the 3-ABC positive reactors in waterbuck, elephant, wildebeest and eland. Contact of wildlife and cattle during utilization of the rich resources in the conservation areas is a potential risk factor for the spread of FMDV in the study area.\n\nConclusionsPresence of FMDV antibodies in cattle and some wildlife were observed and serotypes of FMDV: O, A, SAT-1 and SAT-2 were detected from the 3-ABC positive reactors in some of the wildlife. The study highlights the need for active surveillance of FMDV in wildlife and pastoral cattle within and around wildlife conservation areas in Nigeria. FMD surveillance system, control and prevention program that targets wildlife and livestock at the wildlife-livestock interface level will be beneficial to the livestock industry and wildlife conservation goals in Bauchi State, Nigeria.\n\nAuthor summaryFoot and mouth disease (FMD) is an important trans-boundary viral disease of both domestic and wild cloven hoofed animals characterized by high morbidity with devastating consequence on the livestock worldwide. Despite the endemic nature of FMD in Nigeria, little is known about the epidemiology of the disease at the wildlife-livestock interface level. To address this gap, blood samples were collected between 2013 to 2015 from some wildlife and cattle respectively within and around Yankari Game Reserve (YGR) and Sumu Wildlife Park (SWP) in Bauchi State, Nigeria. Wild animals were immobilized using a combination of Etorphine Hydrochloride (M99(R) Kruger-Med South Africa) at 0.5-2 mg/kg and Azaperone (Stresnil(R), Janssen Pharmaceuticals (Pty.) Ltd., South Africa) at 0.1 mg/kg using a Dan-Inject(R) rifle (Dan-Inject APS, Sellerup Skovvej, Denmark) fitted with 3 ml dart syringe and for reversal, Naltrexone (Trexonil(R) Kruger-Med South Africa) at 1.5 mg IM was used, cattle were restrained by the owners for blood collection. Harvested Sera from blood were screened for presence of Antibodies against FMDV using prioCHECK(R) 3 ABC NSP ELISA kit and positive samples were serotyped using Solid-Phase Competitive ELISA, (IZSLER Brescia-Italy). Out of the 300 and 53 sera collected from cattle and wildlife 197 (65.7%) and 13 (24.5%) (P <0.05) respectively tested positive for antibodies to the highly conserved non-structural 3-ABC protein of FMDV by the FMDV-NS blocking ELISA. Classification of cattle into breed and sex showed that detectable antibodies to FMDV were higher (P <0.05) in White Fulani 157 (72.8%) than red Bororo 23 (39.7%) and Sokoto Gudali 17 (33.3%) breeds of cattle whereas in females detectable FMDV antibodies were higher (P <0.05) 150 (72.8%) than in males 47 (50.0%). In the wildlife species, antibodies to FMDV were detected in waterbuck 2 (28.6%), elephant 1 (25.0%), wildebeest 4 (33.3%) and eland 6 (25.0%). Four serotypes of FMDV: O, A, SAT-1 and SAT-2 were detected from the 3-ABC positive reactors in waterbuck, elephant, wildebeest and elands. The results showed presence of antibodies to FMDV in some wildlife and cattle and suggest that wildlife could equally play an important role in the overall epidemiology of FMD in Nigeria. FMD surveillance system, control and prevention program should be intensified in the study area.

scientific communication and education↗