Pyrethroid insecticides susceptibility profiles and evaluation of L1014F kdr mutant alleles in Culex quinquefasciatus from lymphatic filariasis endemic communities.

This study investigated the dynamics in pyrethriod resistance and the presence/frequencies of L1014F knockdown resistance mutant allelles in Culex quinquefasciatus vector populations from Uruan Local Government Area of AkwaIbom State, Southern Nigeria between the months of March and November, 2021. Uruan LGA is among the endemic LGAs for lymphatic filariasis in AkwaIbomState. Female Anopheles mosquitoes from Eman Uruan, Ituk Mbang and Idu Uruan were exposed to permethrin, deltamethrin and alphacypermethrin in CDC insecticide coated bottles for susceptibility bioassay following standard protocols. The mosquitoes were obtained as aquatic forms from the study sites and reared under laboratory conditions to adults. The adult mosquitoes were used for this study. All the mosquitoes used for the insecticide susceptibility bioassay were morphologically identified. Standard Polymerase chain reaction (PCR) was used for authenticating the Culex quinquefasciatus species. A portion of the vgsc (917 bp) gene spanning the entire intron and the exon containing the L1014F mutation associated with knockdown resistance (kdr) in the vectorswere amplified using Allele-SPECIFIC POLYMERASE CHAIN REACTION (AS-PCR) in order to detect target site insensitivity in the vectors from the study sites. Results obtained revealed that vectors from all the study sites were resistant to permethrin insecticide (mortality rate: 18-23%). Suspected resistance (mortality rate: 90-93%) to deltamethrin and low resistance (mortality rate: 82-85%) to alphacypermethrin insecticides were detected. knockdown was more rapid with deltamethrin and alphacypermethrin than with permethrin across the study sites considering their KDT50 and KDT95. The frequency of the resistant phenotypes ranged from 35.14 to 55.3% across the study sites with a net of 45.1% resistant phenotype recorded in this study. The 1014F allelic frequency calculated from Hardy-Weinberg principle for vector populations across the study sites ranged from 0.500 (50.00%) to 0.7763 (77.63%). All populations witnessed significant (p < 0.05) deviations from Hardy-Weinberg equilibrium in the distribution of these alleles. The findings of this study show that there is a tendency to record an entire population of resistant vectors in this study area over time due to natural selection. The public health implication of these findings is that the use of pyrethroid based aerosols, coils, sprays, LLITNs and others for the purpose of controlling vectors of lymphatic filariasis and other diseases may be effort in futility.

Onchocerciasis transmission status in some endemic communities of Cross River State, Nigeria after two decades of mass drug administration with ivermectin.

Onchocerciasis is a parasitic disease transmitted by black flies. Human onchocerciasis is a public health and socioeconomic problem in Nigeria. Its prevalence and morbidity have reduced over the years because of control efforts especially, Mass Drug Administration with ivermectin. The current goal is to eliminate the disease transmission by 2030. Understanding the changes in transmission patterns in Cross River State is critical to elimination of onchocerciasis in Nigeria. This study was designed to determine the transmission dynamics of onchocerciasis in Cross River State after over two decades of mass ivermectin distribution in endemic communities. Agbokim, Aningeje, Ekong Anaku and Orimekpang are four endemic communities from three Local Government Areas of the State selected for this study. Transmission indices such as infectivity rates, biting rates and transmission potentials, parity rates and diurnal biting activities were determined. A total of 15,520 adult female flies were caught on human baits, Agbokim (2831), Aningeje (6209), Ekong Anaku (4364) and Orimekpang (2116). A total of 9488 and 5695 flies were collected during the rainy and dry seasons respectively in the four communities studied. The differences in relative abundance among the communities were statistically significant (P < 0.001). Monthly and seasonal fly numbers varied significantly (P < 0.008). There were differences in diurnal biting activities of flies in this study at different hours of the day and different months. The peak monthly biting rates were 5993 (Agbokim, October), 13,134 (Aningeje, October), 8680 (Ekong Anaku, October) and 6120 (Orimekpang, September) bites/person/month while the lowest monthly biting rates were 400 (Agbokim, November), 2862 (Aningeje, August), 1405 (Ekong Anaku, January) and 0.0 (Orimekpang, November and December) bites/person/month. Differences in biting rates among the study communities were significant (P < 0.001). The peak monthly transmission potential in Aningeje was 160 infective bites/person/month in the month of February while the lowest (except for months with no transmission) was 42 infective bites/person/month in the month of April. All other study sites had no ongoing transmission in this study. Transmission studies showed that there is progress toward transmission interruption especially in 3 out of the four studied areas. Molecular O-150 poolscreen studies is required to confirm the true transmission situation in the areas.

Evaluation of School-Based Health Education Intervention on the Incidence of Soil-Transmitted Helminths in Pupils of Rural Communities of Eastern Kogi State, North Central Nigeria.

The negative impact of soil-transmitted helminths (STHs) in Nigeria is enormous, and it poses serious public health issues and concerns. This study was undertaken to investigate the impact of health education intervention on reinfection of STHs in pupils of rural schools of Kogi East, North Central Nigeria. A total of 10 schools with the highest prevalence of STHs at baseline were selected from the 45 schools assessed during the baseline survey. These 10 schools were randomly paired into two groups of 5 schools per group. Five schools were dewormed and given health education (DHE) intervention while the other 5 schools were dewormed only (DO) without health education. Reassessment of schools for reinfection was carried out for a period of 12 months. Data obtained were analyzed using descriptive statistics. Student's t-test was used to make comparison between interventions in the incidence of infections. Analysis was carried out at p < 0.05. Reinfection with STHs was observed from the 28th week (7th month) of both interventions with incidence of 0.29 (2 pupils) and 1.00 (7 pupils) in DO and DHE schools, respectively. In the 36th week (9th month), incidence observed in schools given DHE was 0.56 (5 pupils) while incidence of 0.89 (8 pupils) was observed in DO schools, and there was no significant difference (t = -1.000, p = 0.347) between the interventions. At 48th week (12th month), there was no significant difference (t = -0.547, p = 0.599) in incidence between the DHE and DO schools with incidence of 1.00 (12 pupils) and 0.83 (10 pupils), respectively. Hookworms had an incidence of 0.78 (7 pupils) at DHE schools and 0.56 (5 pupils) at DO schools in the 36th week while an incidence of 0.92 (11 pupils) and 0.83 (10 pupils) at DHE and DO schools, respectively, in the 48th week. Ascaris lumbricoides was only observed in DHE schools in a pupil with an incidence of 0.11 (1 pupil) and 0.08 (1 pupil) at 36th and 48th weeks. There was no significant difference in the prevalence of the parasites between DO and DHE intervention groups (p > 0.05). School-based health education intervention had no significant impact on STH incidence in pupils of rural schools in Kogi East. Community-based deworming should be encouraged alongside improvement in the water, sanitation, and hygiene infrastructures and practices at both school and home.

Prevalence, Risk Factors, and Coinfection of Urogenital Schistosomiasis and Soil-Transmitted Helminthiasis among Primary School Children in Biase, Southern Nigeria.

Schistosomiasis and soil-transmitted helminthiasis (STH) are neglected tropical diseases (NTDs) that cause chronic infections and ill health. The study was carried out to determine the current infection status and risk factors associated with Schistosoma haematobium and soil-transmitted helminth (STH) coinfection among school children in Biase Local Government Area (LGA), Cross River State, Nigeria. A cross-sectional study was carried out. Urine and fecal samples were randomly collected from 630 school children in six villages of Biase LGA. Urine sedimentation and Kato-Katz techniques were used to diagnose urogenital schistosomiasis and STHs, respectively. A structured questionnaire was used to collect demographic information and risk factors. The prevalence of S. haematobium in Biase LGA was 6.03%, with males (27 pupils, 9.00%) significantly more (χ 2 = 8.903, p value = 0.003, C.I. = -82.650-120.650) infected than the females (11 pupils, 3.33%), while the prevalence of STH infection was 11.27% with no significant difference (χ 2 = 0.002, p value = 0.962, C.I. = -16.441-54.559) in prevalence between males (34 pupils, 11.33%) and females (37 pupils, 11.21%). Prevalence of S. haematobium and STHs ranged from 1.82 to 19.13% and from 4.55 to 19.05% within the communities, respectively, with Abini (22 pupils, 19.13%) and Adim (20 pupils, 19.05%) communities having the highest prevalence for S. haematobium and STHs, respectively. The most infected age group was 11-13 years (21 pupils, 9.68%) for S. haematobium and 14-16 years (5 pupils, 21.74%) for STHs. Ascaris lumbricoides, hookworms, and Trichuris trichiura had prevalence of 5.56%, 3.02%, and 2.70%, respectively. An overall prevalence of 7.14% and 8.41% was observed for haematuria and proteinuria, respectively. Prevalence of coinfection among the parasites was 4.76%. Male pupils (OR = 2.868, C.I.: 1.397-5.889), pupils of the age group of 11-13 years (OR = 2.496, C.I.: 1.287-4.838), school children that swim (OR = 1.527, C.I.: 0.784-2.974), those that cross streams to farm (OR = 25.286, C.I.: 4.091-156.283), those that visit stream or river severally (OR = 3.077, C.I.: 1.204-7.863), and those whose home is 1 km (OR = 3.116, C.I.: 1.292-7.518) from the stream are at higher odds of infection with S. haematobium. For STHs, male pupils (OR = 1.012, C.I.: 0.617-1.659), pupils of the age group of 11-13 years (OR = 2.609, C.I.: 1.582-4.302), pupils that walk barefoot (OR = 18.746, C.I.: 6.786-51.783), those that do not wash fruits and vegetables before eating (OR = 2.334, C.I.: 1.400-3.892), those that do not wash hands after using the toilet (OR = 1.200, C.I.: 0.730-1.973), those that eat soils (OR = 2.741, C.I.: 1.533-4.902), those that drink water from streams or rivers (OR = 189.509, C.I.: 24.807-1447.740), and those that use pit latrine (OR = 2.920, C.I.: 1.746-4.885) and/or open defecation (OR = 2.552, C.I.: 1.454-4.479) are at high odds of being infected with STHs. Urogenital schistosomiasis and soil-transmitted helminthiasis are still endemic diseases in Biase LGA. Although the degree of infection is quite low or moderate, there is a need to intensify and sustain control measures such as provision of sustainable clean water supply, health education intervention, and chemotherapy.

Edaphic and climatic factors influence on the distribution of soil transmitted helminths in Kogi East, Nigeria.

The need for a reliable risk map in the control of soil-transmitted helminths (STHs) in Kogi East, North Central Nigeria is very important. This study was carried out to determine the effect of environmental risk factors on geospatial distribution of STHs. Epidemiological data were obtained from a district-wide survey conducted in 2018 in Kogi East. Edaphic and climatic factors were downloaded as spatial layers from international recognised health data resources centres. A total of 24 environmental factors were used in determining the risk map of STHs using MaxEnt tool. The predicted high-risk areas of A. lumbricoides, hookworms and S. stercoralis were the central part of Kogi East covering parts of Dekina, Ofu, Igalamela-Odolu, Olamaboro and Omala LGAs with probability of 0.8 to 1.00. Among the factors investigated; Temperature [mean diurnal temperature range (BIO2), temperature annual range (BIO7) and maximum temperature of the warmest month (BIO5)], precipitation [precipitation of the wettest quarter (BIO16)], and soil clay contents were the five factors that exerted most significant influence on the geospatial distribution of STHs in Kogi East, Nigeria. Public health control programmes on STHs should target high-risk areas by including them in mass drug administration, health education as well as provision of water, sanitation and hygiene infrastructures.

Infection pattern, case fatality rate and spread of Lassa virus in Nigeria.

BACKGROUND: Lassa fever (LF) is a zoonotic infectious disease of public concern in Nigeria. The infection dynamics of the disease is not well elucidated in Nigeria. This study was carried out to describe the pattern of infection, case fatality rate and spread of lassa virus (LASV) from 2017 to 2020. METHODS: Weekly epidemiological data on LF from December, 2016 to September, 2020 were obtained from Nigeria Centre for Disease Control. The number of confirmed cases and deaths were computed according to months and states. Descriptive statistics was performed and case fatality rate was calculated. Distribution and spread maps of LF over the four years period was performed on ArcMap 10.7. RESULTS: A total of 2787 confirmed cases and 516 deaths were reported in Nigeria from December, 2016 to September, 2020. Increase in number of cases and deaths were observed with 298, 528, 796 and 1165 confirmed cases and 79, 125, 158 and 158 deaths in 2017, 2018, 2019 and 2020 respectively. Over 60% of the cases were reported in two states, Edo and Ondo states. The LF cases spread from 19 states in 2017 to 32 states and Federal Capital Territory (FCT) in 2020. Ondo state (25.39%) had the highest of deaths rate from LF over the four years. Case fatality rate (CFR) of LF was highest in 2017 (26.5%) with CFR of 23.7, 19.6 and 13.4% in 2018, 2019 and 2020 respectively. The peak of infection was in the month of February for the four years. Infections increases at the onset of dry season in November and decline till April when the wet season sets-in. CONCLUSION: There is an annual increase in the number of LASV infection across the states in Nigeria. There is need to heighten control strategies through the use of integrated approach, ranging from vector control, health education and early diagnosis.