No abstract

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

BackgroundDespite 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.MethodsApplication 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.ResultsA 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).ConclusionsThe 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.Electronic supplementary materialThe online version of this article (10.1186/s12936-018-2344-z) contains supplementary material, which is available to authorized users.

Abstract. Adelaja OJ, Oduola AO, Abiodun OO, Adeneye AK, Obembe A. 2021. Plants with insecticidal potential used by ethnic groups in North-Central Nigeria for the management of hematophagous insects. Asian J Ethnobiol 4: 65-75. Studies on the traditional knowledge of insecticidal plants are vital in the discovery of bioactive components for the management of hematophagous insects. This study investigated the ethnobotany and traditional knowledge of insecticidal plants among nine ethnic groups in North-Central Nigeria. Information on identifying insecticidal plants and their traditional knowledge among community leaders, elders, herb sellers, and herbalists was collected between January and December 2017, using a semi-structured questionnaire. The mentioned plants were collected and identified. A total of 388 respondents were interviewed from nine ethnic groups. All the respondents had knowledge of medicinal and insecticidal plants in their communities. The respondents mentioned 17 insecticidal plants. The most frequently mentioned plants were Hyptis suaveolens (19.6%, 76/388), Ocimum gratissimum (18.7%, 73/388), and Citrus sinensis (10.8%, 42/388). Hanging of plants in homes was reported among 52.9% of the respondents and smoldering for personal protection among 47.1%. The respondents also acknowledged that these plants were available (88.4%), accessible (77%), and very effective (76.3%) in controlling hematophagous insects. There was a significant relationship (P<0.05) between the perceived efficacy of these plants and the gender, age, educational status, and ethnicity of respondents. This study documented the knowledge and evidence of insecticidal plants among ethnic groups in North-Central Nigeria.

Man, in a desperate bid to manage malaria-vectors, i.e., Anopheles gambiae s. l. (Diptera: Culicidae) has relentlessly relied on pyrethroid insecticides especially Permethrin. Unfortunately, these mosquitoes have improved their survival with respect to this approach which must have been associated with some fitness-costs. This study, therefore, evaluates the biological fitness-costs associated with permethrin-resistance development in An. gambiae s.l. in Kwara State, Nigeria. Susceptibility statuses of adult female An. gambiae s.l. populations collected from Oke-odo, Pipeline and Airport were established using World Health Organization test protocol. They were subsequently raised over three-generations and the fecundity, hatchability, development time for larvae, pupae and adult, adult emergence, adult sex ratio was observed, noted, monitored and analysed using ANOVA (P<0.05). Permethrin-resistant, moderately-resistant and susceptible status were each observed in the An. gambiae s.l. populations of Oke-odo, pipeline and Airport, respectively. The biological fitness-costs showed that permethrin-resistant An. gambiae s.l. had reduced fecundity (First generation (F1) = 86.07%, Second generation (F2) = 84.55% and Third generation (F3) = 100%) and hatchability (F1=96.58%, F2=92.02% and F3=100%). Also, there were reduced larvae developmental-time (F1=35.71% and F2=42.86%), adult-emergence (F1=97.69%) and longevity (F1=46.39%) when compared with the susceptible population. Permethrin-resistance development in An. gambiae s.l. definitely comes with some biological fitness-costs that disadvantage its transmission potential and can be leveraged upon in vector-management.