Entomological surveillance of local malaria vector populations is an important component of vector control and resistance management. In this study, the resistance profile and its possible mechanisms was characterised in a field population of the major malaria vector Anopheles coluzzii from Port Harcourt, the capital of Rivers state, in the Niger-Delta Region of Nigeria. Larvae collected in Port-Harcourt, were reared to adulthood and used for WHO bioassays. The population exhibited high resistance to permethrin, deltamethrin and DDT with mortalities of 6.7% ± 2.4, 37.5% ± 3.2 and 6.3% ± 4.1, respectively, but were fully susceptible to bendiocarb and malathion. Synergist bioassays with piperonylbutoxide (PBO) partially recovered susceptibility, with mortalities increasing to 53% ± 4, indicating probable role of CYP450s in permethrin resistance (χ2 = 29.48, P < 0.0001). Transcriptional profiling revealed five major resistance-associated genes overexpressed in the field samples compared to the fully susceptible laboratory colony, Ngoussou. Highest fold change (FC) was observed with GSTe2 (FC = 3.3 in permethrin exposed and 6.2 in unexposed) and CYP6Z3 (FC = 1.4 in exposed and 4.6 in unexposed). TaqMan genotyping of 32 F0 females detected the 1014F and 1575Y knockdown resistance (kdr) mutations with frequencies of 0.84 and 0.1, respectively, while 1014S mutation was not detected. Sequencing of a fragment of the voltage-gated sodium channel, spanning exon 20 from 13 deltamethrin-resistant and 9 susceptible females revealed only 2 distinct haplotypes with a low haplotype diversity of 0.33. The findings of high pyrethroid resistance but with a significant degree of recovery after PBO synergist assay suggests the need to move to PBO-based nets. This could be complemented with carbamate- or organophosphate-based indoor residual spraying in this area.

Aim: To determine the occurrence of entomophilous and soil transmitted nematodes of three insect species; Zonocerus variegatus, Gryllotalpa orientalis and Mantis religiosa in Obio Akpor, Local Government Area of Rivers State, Nigeria. Methodology: The insect samples were collected with entomological sweep net as described by Colwell [1] and pitfall traps as described by Davies [2]. Insect samples were dissected using Stubbins’ method [3] while nematodes in the insects were isolated and identified according to Cheesborough, (2005). Results: Two hundred and forty-eight (248) insect specimens comprising; Z. variegatus 193 (77.8%), G. orientalis 42(16.9%) and Mantis religiosa 13(5.2%) were collected from designated ecological settings based on availability and trapping efficiency. Out of the 248 insects sampled; 145 (58.5%) were infected with three genera of nematodes comprising; Ascaris lumbricoides; 17 (7.5%), Mermis Spp., 148 (65.5%) and Trilabiatus lignicolus 61(27.0%). Mermis Spp., an entomophilous nematode occurred in Z. variegatus and Mantis religiosa due to host specific factors. Nematode occurrence in the host did not indicate sex relationship (P>0.05) however, hosts age influenced parasite occurrence as older insects harbored more parasites (P<0.05). Trilabiatus lignicolus; a free-living soil nematode and A. lumbricoides; a soil transmitted helminthes found in the guts of Z. variegatus and G orientalis was attributed to the feeding habits of the insects. Conclusion: The study indicated that Z. variegatus and G. orientalis as veritable vectors of soil transmitted nematodes while Z. variegatus and Mantis religiose are suitable host of the entomophilous nematode Mermis Spp.

Background: The United Nations Inter-Agency and Expert Group on Millennium Development Goals (MDGs), established incidence rate as one of the indicators for monitoring progress on Malaria control. Data on malaria incidence rates in Edo State, Nigeria, 2006-2013 were published in 2015. The current study focused on incidence rates, 2014-2018. In addition, trends in malaria diagnoses were also investigated. Methods: Records of numbers of patients from the 18 Local Government Areas (LGAs) complaining of malaria, at LGA Health Centres, State Hospitals, etc. were obtained from the Department of Disease Control, State Ministry of Health, Benin City. Patients were placed in 3 categories: Fever, without malaria confirmation, confirmed uncomplicated, confirmed severe. Human population records over the 5-year period were obtained from the Nigeria Population Commission, Benin City. Incidence rates were calculated and relative proportions of patients in the 3 categories determined. Results: The numbers of fever cases, without malaria confirmation, varied across LGAs and constituted 58.00-68.00% of all fever cases annually. In confirmed cases of malaria, most were uncomplicated. The highest numbers of confirmed cases were in Egor and Oredo LGAs. The pattern was similar in uncomplicated and severe cases. The ratios of uncomplicated and severe cases of malaria varied significantly (p<0.05) annually. Malaria incidence rates varied among LGAs in each of the years: 2014 (0.75-5.48%), in 2015 (0.24-2.55%), in 2016 (1.44-5.21%), in 2017 (1.17-9.69%), in 2018 (0.63-4.03%). However, these differences were not significant (p>0.05). In the period 2014-2018, malaria incidence rates of 5.00% and above were recorded only 5times across LGAs: Egor, 2014 (5.48%); Esan Central, 2016 (5.14%; Ovia southwest, 2016 (5.21%), 2017 (9.69%); Uhunmwnde, 2017 (5.05%). Conclusion: The decline in malaria incidence rates, 2014-2018, over the 2006-2013 data indicates progress. However, there are still daunting challenges which have been detailed in the text. These results also highlight the need for malaria test confirmation rather than utilizing fever as the exclusive symptom for malaria. All stakeholders must intensify efforts to ensure that this downward trend in malaria incidence rates is sustained.

Background Forensic entomology is evolving into entomotoxicology, which is a critical approach in forensic toxicology that alternatively assesses presence of toxins in insects that have eaten a decomposing cadaver. Toxic substances in or on a dead body may accumulate in the tissues of fly maggots while feeding on the body and thus may alter their developmental rate. Thus, four out of eight healthy pigs (Sus scrofa Linn.) that weighed on the average 22.3 ± 1.9 kg were sacrificed with zinc phosphide as food poison, while the remaining four pigs were sacrificed by strangulation during the rainy and dry seasons of 2014 and 2015 respectively. Their bodies were deposited in a building to mimic indoor decomposition. The building is on 6° 15′ 18.06″ N and 7° 06′ 41.37″ E at Nnamdi Azikiwe University Awka, Anambra State, Nigeria. The effect of the zinc phosphide on the decomposition duration of the cadavers was monitored. Toxicological assessment of zinc and phosphorus on maggots found on the cadavers was performed with an atomic absorption spectrophotometer. Findings The zinc phosphide did not affect the decomposition duration of the cadaver and did not prolong or shortened the life cycle of the fly maggots when compared with the control (strangled pig cadaver). For the poisoned cadavers, the atomic absorption spectrophotometer detected zinc in the maggot tissues collected from them while phosphorus was not detected. Neither zinc nor phosphorus was detected in the maggot tissues collected from the strangled cadavers. Conclusions The study showed that the zinc component in the zinc phosphide commonly used as rodenticide in Awka can be detected in maggots collected from such a suspected poisoned cadaver. Other implications related to toxicological studies on cadaveric insects in forensic entomology and serving as alternative matrices in forensic toxicology in any questionable death were also highlighted.

Dipteran maggots found on a cadaver are used to estimate its time of death but the time may be incorrect if death occurred due to ingestion of poison. Decomposition of a zinc phosphide intoxicated and strangulated pigs (Sus scrofa Linn.) were evaluated in this study. They were deposited in a forest during the rainy season and repeated during the dry season at Awka, Nigeria. Decomposition duration and stages of decay of the pig cadavers were recorded. Maggots found on the cadavers were collected, reared to adulthood and were identified. Similar maggot samples were assessed for residues of zinc and phosphorus with an Atomic Absorption Spectrophotometer. Both pig cadavers completely decomposed within 10 and 14 days during the rainy and dry seasons, respectively. Appearance and emergence of three dipteran maggot families were observed on the cadavers in a successional pattern. Zinc and phosphorus residues were detected in the maggots from the poisoned cadavers while they were not detected in the maggots from the strangled cadavers. The three dipteran maggot families are recommended as a valuable tool in forensic entomology for the estimation of elapsed time of a questionable death and the dipteran bodies would also be useful for toxicological analysis.