Papers by adelaja J olukayode
Nigerian Journal of Parasitology, 2016
Indoor resting mosquitoes were collected between November 2013 and May 2014 using Pyrethrum spray... more Indoor resting mosquitoes were collected between November 2013 and May 2014 using Pyrethrum spray collection (PSC). The mosquitoes were identified using morphological keys and species specific polymerase chain reaction (PCR) assays. The species composition of members of the An. gambiae complex and reported malaria cases in the selected study communities were spatially mapped using Arc GIS software. A total of 645 mosquitoes were collected from the study sites and morphologically identified. This comprised of 598 (92%) Anopheles species, 42 (7%) Culex species and 5 (1%) Aedes species. One hundredand ninety-six An. gambiaes. l. samples were randomly selected and successfully identified by PCR. The composition of the mosquitoes species collected in Gaa Bolohunduro showed that a higher proportion 53 (64.6%) were An. arabiensis compared to lower proportions 5(6.1%) of An. coluzzii and 24 (29.3%) An. gambiae . In Osin, only 12 (10.5%) were An. arabiensis compared to 13 (11.4%) and 89 (78.1%) identified as An. coluzzii and An. gambiae respectively. The variation in the composition of members of the An. gambiaes. l. identified in Gaa Bolohunduro was not significant ( p =0.070) compared to Osin ( p =0.043). A weak correlation coefficient showed that the predominance of Anopheles in both communities was not dependent on rainfall, though variation in the members of the complex within the wet and dry season was significant ( p <0.01). The sympatric occurrence and availability of An. gambiaes. s. and An. arabiensis during the dry and wet seasons corroborated the high malaria prevalence identified in Ilorin South. This suggests that both vectors will sustain malaria transmission in the study sites. Hence, a vector control strategy in these localities should be informed by the individual behaviour of each vector species identified. Keywords: Anopheles arabiensis, Anopheles coluzzi, Anopheles gambiae , distribution, composition, malaria case
Acta Tropica, Mar 1, 2022
Malaria is a major public health challenge in Africa with Nigeria accounting for the highest burd... more Malaria is a major public health challenge in Africa with Nigeria accounting for the highest burden of the disease in the world. Vector control has proved to be a highly effective component of malaria control, however, the development and spread of insecticide resistance in major vectors of malaria have been a major challenge. This study assessed resistance mechanisms in Anopheles coluzzii populations from Kosofe, Lagos mainland and Ojo Local Government Areas in Lagos, Nigeria where An. gambiae s.l is resistant to DDT and Permethrin. WHO susceptibility bioassay test was used in determining resistance status of An. coluzzii to discriminating doses of DDT and Permethrin while synergist assay was used to assess the involvement of monooxygenases in resistance development. Sub-species of An. gambiae s.l (An. gambiae and An. coluzzii) were identified using polymerase chain reaction (PCR) and Restriction Fragment Length Polymorphism (PCR-RFLP) while Allele-Specific Polymerase Chain Reaction (AS-PCR) assay was used to detect knockdown mutation (kdr-West; L1014F). Biochemical assays were used in determining the activities of metabolic enzymes. High DDT resistance was recorded in An. coluzzii populations from the three sites. Mortality rate of mosquitoes exposed confirmed Permethrin resistance in Kosofe (50%) and Lagos mainland (48%) but resistance was suspected in Ojo (96%). All specimens tested were confirmed as An. coluzzii with low kdr frequency; 11.6%, 16.4% and 6.7% in Kosofe, Lagos mainland and Ojo respectively. Pre-exposure to synergist; PBO before exposure to Permethrin led to increased mortality in all populations. Esterase activity was insignificantly overexpressed in Kosofe (p = 0.849) and Lagos mainland (p = 0.229) populations. In contrast, GST activity was significantly lower in populations from Lagos mainland (63.650 ± 9.861; p = 0.007) and Ojo (91.765 ± 4.959; p = 0.042) than Kisumu susceptible strains (120.250 ± 13.972). Monooxygenase activity was higher in Lagos mainland (2.371 ± 0.261) and Ojo (1.361 ± 0.067) populations, albeit significantly in Lagos mainland (p = 0.007) only. Presence of target-site mutation in all populations, increased mortality with pre-exposure to PBO and elevated monooxygenase in Lagos mainland were confirmed. Multiple resistance mechanisms in some urban populations of An. coluzzii from Lagos, Nigeria calls for appropriate resistance management strategies.
Malaria journal, Jan 15, 2018
Despite the availability of effective malaria vector control intervention tools, implementation o... more Despite the availability of effective malaria vector control intervention tools, implementation of control programmes in Nigeria is challenged by inadequate entomological surveillance data. This study was designed to assess and build the existing capacity for malaria vector surveillance, control and research (MVSC&R) in Nigerian institutions. Application call to select qualified candidates for the capacity building (CB) intervention training programme was advertised in a widely read newspaper and online platforms of national and international professional bodies. Two trainings were organized to train selected applicants on field activities, laboratory tools and techniques relevant to malaria vector surveillance and control research. A semi-structured questionnaire was administered to collect data on socio-demographic characteristics of participants, knowledge and access of participants to field and laboratory techniques in MVSC&R. Similarly, pre and post-intervention tests were cond...
Journal of Arthropod-Borne Diseases
Background: Timely entomological and insecticide resistance monitoring is a key to generating rel... more Background: Timely entomological and insecticide resistance monitoring is a key to generating relevant data for vector management. We investigated the insecticide susceptibility status of Anopheles gambiae s.l. in eight rural farming communities in Southern Gombe, Nigeria. Methods: Overall, 3–5 days-old adult female Anopheles mosquitoes reared from field-collected immature stages between September and November, 2014 were exposed to the diagnostic doses of pyrethroids, organophosphate and carbamate insecticides using the Center for Disease Control Bottle bioassay. The observatory knockdown time from exposure to each insecticide was recorded up to two hours. The dead mosquitoes were then identified morphologically and by molecular assays. Results: Mortality results showed resistance in An. gambiae s.l. populations to bendiocarb (2.3–100%), deltamethrin (39–70%), pirimiphos-methyl (65–95%), dichloro-diphenyl-trichloroethane (0–38.1%), permethrin (0–46.3%) and lambda-cyhalothrin (42.5–...
Indoor resting mosquitoes were collected between November 2013 and May 2014 using Pyrethrum spray... more Indoor resting mosquitoes were collected between November 2013 and May 2014 using Pyrethrum spray collection (PSC). The mosquitoes were identified using morphological keys and species specific polymerase chain reaction (PCR) assays. The species composition of members of the An. gambiae complex and reported malaria cases in the selected study communities were spatially mapped using Arc GIS software. A total of 645 mosquitoes were collected from the study sites and morphologically identified. This comprised of 598 (92%) Anopheles species, 42 (7%) Culex species and 5 (1%) Aedes species. One hundredand ninety-six An. gambiaes. l. samples were randomly selected and successfully identified by PCR. The composition of the mosquitoes species collected in Gaa Bolohunduro showed that a higher proportion 53 (64.6%) were An. arabiensis compared to lower proportions 5(6.1%) of An. Coluzzii and 24 (29.3%) An. gambiae. In Osin, only 12 (10.5%) were An. arabiensis compared to 13 (11.4%) and 89 (78.1...
Research paper, 2019
Background: Timely entomological and insecticide resistance monitoring is a key to generating rel... more Background: Timely entomological and insecticide resistance monitoring is a key to generating relevant data for vector management. We investigated the insecticide susceptibility status of Anopheles gambiae s.l. in eight rural farming communities in Southern Gombe, Nigeria. Methods: Overall, 3-5 days-old adult female Anopheles mosquitoes reared from field-collected immature stages between September and November, 2014 were exposed to the diagnostic doses of pyrethroids, organophosphate and carbamate insecticides using the Center for Disease Control Bottle bioassay. The observatory knockdown time from exposure to each insecticide was recorded up to two hours. The dead mosquitoes were then identified morphologically and by molecular assays. Results: Mortality results showed resistance in An. gambiae s.l. populations to bendiocarb (2.3-100%), deltamethrin (39-70%), pirimiphos-methyl (65-95%), dichloro-diphenyl-trichloroethane (0-38.1%), permethrin (0-46.3%) and lambda-cyhalothrin (42.5-86.4%). The few cases of full susceptibility were observed from lamdacyhalothrin exposed population of An. gambiae s.l. in Banbam and Pantami respectively. An. gambiae 177 (45%) was significantly higher (P< 0.05) than An. arabiensis 64 (16.3%), An. coluzzii 34 (8.7%) and An. gambiae/An. coluzzii hybrid 78 (19.8%). Conclusion: A strong evidence of widespread resistance in the major malaria vector species in Southern Gombe to all common classes of insecticides is a justification for the State Malaria Elimination Programme to consciously consider incorporating insecticide resistance management strategies into control programs in order to sustain the future of current control interventions.
J Arthropod-Borne Dis, 2019
Background: Timely entomological and insecticide resistance monitoring is a key to generating rel... more Background: Timely entomological and insecticide resistance monitoring is a key to generating relevant data for vector management. We investigated the insecticide susceptibility status of Anopheles gambiae s.l. in eight rural farming communities in Southern Gombe, Nigeria. Methods: Overall, 3-5 days-old adult female Anopheles mosquitoes reared from field-collected immature stages between September and November, 2014 were exposed to the diagnostic doses of pyrethroids, organophosphate and carbamate insecticides using the Center for Disease Control Bottle bioassay. The observatory knockdown time from exposure to each insecticide was recorded up to two hours. The dead mosquitoes were then identified morphologically and by molecular assays. Results: Mortality results showed resistance in An. gambiae s.l. populations to bendiocarb (2.3-100%), deltamethrin (39-70%), pirimiphos-methyl (65-95%), dichloro-diphenyl-trichloroethane (0-38.1%), permethrin (0-46.3%) and lambda-cyhalothrin (42.5-86.4%). The few cases of full susceptibility were observed from lamdacyhalothrin exposed population of An. gambiae s.l. in Banbam and Pantami respectively. An. gambiae 177 (45%) was significantly higher (P< 0.05) than An. arabiensis 64 (16.3%), An. coluzzii 34 (8.7%) and An. gambiae/An. coluzzii hybrid 78 (19.8%). Conclusion: A strong evidence of widespread resistance in the major malaria vector species in Southern Gombe to all common classes of insecticides is a justification for the State Malaria Elimination Programme to consciously consider incorporating insecticide resistance management strategies into control programs in order to sustain the future of current control interventions.
Background: Despite the availability of effective malaria vector control intervention tools, impl... more Background: Despite the availability of effective malaria vector control intervention tools, implementation of control programmes in Nigeria is challenged by inadequate entomological surveillance data. This study was designed to assess and build the existing capacity for malaria vector surveillance, control and research (MVSC&R) in Nigerian institutions. Methods: Application call to select qualified candidates for the capacity building (CB) intervention training programme was advertised in a widely read newspaper and online platforms of national and international professional bodies. Two trainings were organized to train selected applicants on field activities, laboratory tools and techniques relevant to malaria vector surveillance and control research. A semi-structured questionnaire was administered to collect data on socio-demographic characteristics of participants, knowledge and access of participants to field and laboratory techniques in MVSC&R. Similarly, pre and post-intervention tests were conducted to assess the performance and improvement in knowledge of the participants. Mentoring activities to sustain CB activities after the training were also carried out. Results: A total of 23 suitable applicants were shortlisted out of the 89 applications received. The South West, South East and North Central geopolitical zones of the country had the highest applications and the highest selected number of qualified applicants compared to the South South and North East geopolitical zones. The distribution with respect to gender indicated that males (72.7%) were more than females (27.3%). Mean score of participants' knowledge of field techniques was 27.8 (± 10.8) before training and 67.7 (± 9.8) after the training. Similarly, participants' knowledge on laboratory techniques also improved from 37.4 (± 5.6) to 77.2 (± 10.8). The difference in the mean scores at pre and post-test was statistically significant (p < 0.05). Access of participants to laboratory and field tools used in MVSC&R was generally low with insecticide susceptibility bioassays and pyrethrum spray collection methods being the most significant (p < 0.05). Conclusions: The capacity available for vector control research and surveillance at institutional level in Nigeria is weak and require further strengthening. Increased training and access of personnel to relevant tools for MVSC&R is required in higher institutions in the six geopolitical zones of the country.
Conventional pesticides are the focal and mainstay tools being used in the control of mosquitoes.... more Conventional pesticides are the focal and mainstay tools being used in the control of mosquitoes. However, some of these pesticides are known to cause acute and long term health problems in man. Moreso that they constitute to the existing environmental pollution, there is therefore an urgent need to explore the effectiveness of biolarvicides which is usually considered as a safe alternative to these conventional pesticides. A thorough understanding of the fate and efficacy of biolarvicide formulations in mosquito breeding sites open to water fluctuations is required for effective implementation of larval source management programmes. This study investigated the colony progression and impact of Bacillus sp on the larval gut of Culex quinquefasciatus. rd Twenty 3 instar larvae of C. quinquefasciatus mosquitoes were introduced into each of the three replicates of-6-7-8-9 ® plastic beakers containing one litre of serial dilutions (1x10 , 1x10 , 1x 10 and 1 x10) of VectoMax CG concentrations. Mean larval mortality of mosquitoes in each concentration was calculated hourly over a 24-hour period. The concentration that induced 100% mortality under the shortest exposure period was chosen as the dosage to be evaluated for its colony forming units in the larval gut exposed. Surface sterilization of mosquito larvae and work space was carried out following standard techniques after which the mosquito guts were dissected and plated on nutrient agar. Discrete colonies on each of the replicated plates were counted using colony counter. The time taken to achieve 100% mortality of Culex quinquefasciatus after exposure to-6-7-8 10 , 10 and 10 serial dilutions of the larvicides increased from 6-10 hours with an increasing dilution ratio.-9 The least concentration of the microbial larvicide (10) induced 96 % mortality in the Culex population at 16 hours of exposure. The significant mean count of Bacillus sp found in the gut of Culex quinquefasciatus and ® the lethal impact at reduced concentrations have shown that VectoMax CG could be a useful Larval Source Management tool in habitat settings open to water fluctuations.
Bedbugs are cosmopolitan insects of public health importance. Their characteristic biting and blo... more Bedbugs are cosmopolitan insects of public health importance. Their characteristic biting and blood feeding activities result in both physical symptoms and psychological distress in affected hosts. This study investigated the incidence of bedbug and control practices among students and indigenes living in two different settlements in Ilorin, Nigeria. Bedbug were surveyed and collected from household materials from fifty apartments randomly selected from each of the new and old student hostels and family houses in Tanke and Oja-Oba area of Ilorin. Bedbugs collected were persevered in 70 % alcohol and identified using taxonomic keys. A structured questionnaire was used to obtain information on respondent's demography, perception about bedbug infestation and control practices in sampled houses in the study areas. Sampled data were analysis using percentages. Results from the survey revealed that the number of respondents with knowledge of bedbug was not significant (p>0.05) compared with those without. Family houses in indigenous Oja-Oba study location were the only site with bed-bug infestation. Higher numbers of bedbugs were collected on mattresses. Out of the 200 respondents, 20 (10 %) employed the use of chemical method in bedbug control and precisely, 12 (60 %) of these use a locally made formulation named otapiapia. The intensity of infestation in Oja-Oba and insignificant knowledge of bedbug among the respondents suggest the need to raise the level of public awareness and also canvass for an improved living conditions in the affected areas.
Vector control programs in Nigeria are mostly targeted towards reducing the burden of malaria wit... more Vector control programs in Nigeria are mostly targeted towards reducing the burden of malaria with less emphasis placed on other debilitating vector borne diseases such as dengue, yellow fever and filariasis. This study assessed the indoor resting densities and insecticide susceptibility status of Culex and Aedes mosquitoes in selected communities utilizing long-lasting insecticidal nets (LLIN) in Kwara State, Nigeria. Pyrethrum spray collections of indoor resting Aedes and Culex mosquitoes were conducted in three communities while adults of both mosquito species reared from larval collections were exposed to pyrethroid, organochlorine, and carbamate insecticides following WHO procedure. Results showed that the higher indoor resting densities of Culex quinquefasciatus (2.5 – 3.4) collected were not significantly (p>0.05) different from the Aedes aegypti (0.3 – 1.3) in all the communities. Carbamate resistance (≤ 81 % post exposure mortalities) was observed in both Culex (Ilota and Amoyo) and Aedes populations (Gaa-Bolorunduro). Aedes in Gaa-Bolorunduro and Ilota were fully susceptible (100 % mortality) to permethrin and DDT while the Culex population showed differential susceptibility (64 – 100%) to pyrethroid and organochlorine insecticides tested. These findings show focal insecticide resistance requiring specific intervention in each community based on the evidence provided by this study. Pyrethroid resistance status of the Culex quinquefasciatus in these areas may result in access of the vectors to net occupants leading to lower LLIN utilization rates among users. Environmental management strategy in addition to the use of effective insecticide will be most probable for management of vector borne diseases in these localities.
Vector control programs in Nigeria are mostly targeted towards reducing the burden of malaria wit... more Vector control programs in Nigeria are mostly targeted towards reducing the burden of malaria with less emphasis placed on other debilitating vector borne diseases such as dengue, yellow fever and filariasis. This study assessed the indoor resting densities and insecticide susceptibility status of Culex and Aedes mosquitoes in selected communities utilizing long-lasting insecticidal nets (LLIN) in Kwara State, Nigeria. Pyrethrum spray collections of indoor resting Aedes and Culex mosquitoes were conducted in three communities while adults of both mosquito species reared from larval collections were exposed to pyrethroid, organochlorine, and carbamate insecticides following WHO procedure. Results showed that the higher indoor resting densities of Culex quinquefasciatus (2.5 – 3.4) collected were not significantly (p>0.05) different from the Aedes aegypti (0.3 – 1.3) in all the communities. Carbamate resistance (≤ 81 % post exposure mortalities) was observed in both Culex (Ilota and Amoyo) and Aedes populations (Gaa-Bolorunduro). Aedes in Gaa-Bolorunduro and Ilota were fully susceptible (100 % mortality) to permethrin and DDT while the Culex population showed differential susceptibility (64 – 100%) to pyrethroid and organochlorine insecticides tested. These findings show focal insecticide resistance requiring specific intervention in each community based on the evidence provided by this study. Pyrethroid resistance status of the Culex quinquefasciatus in these areas may result in access of the vectors to net occupants leading to lower LLIN utilization rates among users. Environmental management strategy in addition to the use of effective insecticide will be most probable for management of vector borne diseases in these localities.
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Papers by adelaja J olukayode