Description of the design of a mixed-methods study to assess the burden and determinants of malaria transmission for tailoring of interventions (microstratification) in Ibadan and Kano metropolis.

BACKGROUND: Rapid urbanization in Nigerian cities may lead to localized variations in malaria transmission, particularly with a higher burden in informal settlements and slums. However, there is a lack of available data to quantify the variations in transmission risk at the city level and inform the selection of appropriate interventions. To bridge this gap, field studies will be undertaken in Ibadan and Kano, two major Nigerian cities. These studies will involve a blend of cross-sectional and longitudinal epidemiological research, coupled with longitudinal entomological studies. The primary objective is to gain insights into the variation of malaria risk at the smallest administrative units, known as wards, within these cities. METHODS/RESULTS: The findings will contribute to the tailoring of interventions as part of Nigeria's National Malaria Strategic Plan. The study design incorporates a combination of model-based clustering and on-site visits for ground-truthing, enabling the identification of environmental archetypes at the ward-level to establish the study's framework. Furthermore, community participatory approaches will be utilized to refine study instruments and sampling strategies. The data gathered through cross-sectional and longitudinal studies will contribute to an enhanced understanding of malaria risk in the metropolises of Kano and Ibadan. CONCLUSIONS: This paper outlines pioneering field study methods aimed at collecting data to inform the tailoring of malaria interventions in urban settings. The integration of multiple study types will provide valuable data for mapping malaria risk and comprehending the underlying determinants. Given the importance of location-specific data for microstratification, this study presents a systematic process and provides adaptable tools that can be employed in cities with limited data availability.

Geospatial distribution and predictive modeling of onchocerciasis in Ogun State, Nigeria.

Onchocerciasis caused by infection with Onchocerca volvulus is a disease of public health importance and is highly associated with disability. As Nigeria is aiming at eliminating onchocerciasis by 2030, there is a need to develop newer tools to map disease prevalence and identify environmental factors driving disease prevalence, even in places that have not been previously targeted for preventive chemotherapy. This study produced predictive risk-maps of onchocerciasis in Ogun State. Georeferenced onchocerciasis infection data obtained from a cross-sectional survey at 32 locations between March and July 2015 together with remotely-sensed environmental data were analyzed using Ecological Niche Models (ENM). A total of 107 field occurrence points for O. volvulus infection were recorded. A total of 43 positive occurrence points were used for modelling. ENMs were used to estimate the current geographic distribution of O. volvulus in Ogun State. Maximum Entropy distribution modeling (MaxEnt) was used for predicting the potential suitable habitats, using a portion of the occurrence records. A total of 19 environmental variables were used to model the potential geographical distribution area under current climatic conditions. Empirical prevalence of 9.3% was recorded in this study. The geospatial distribution of infection revealed that all communities in Odeda Local Government Area (a peri-urban LGA) showed remarkably high prevalence compared with other LGAs. The predicted high-risk areas (probability > 0.8) of O. volvulus infection were all parts of Odeda, Abeokuta South, and Abeokuta North, southern part of Imeko-Afon, a large part of Yewa North, some parts of Ewekoro and Obafemi-Owode LGAs. The estimated prevalence for these regions were >60% (between 61% and 100%). As predicted, O. volvulus occurrence showed a positive association with variables reflecting precipitation in Ogun State. Our predictive risk-maps has provided useful information for the elimination of onchocerciais, by identifying priority areas for delivery of intervention in Ogun State, Nigeria.

Profiling the knowledge of female medical/para-medical students, and expertise of health care professionals on female genital schistosomiasis in Anambra, South Eastern Nigeria.

BACKGROUND: Female genital schistosomiasis (FGS) is a largely neglected tropical disease (NTD), with little or no attention in the primary health care unit. Towards building momentum to address this challenge, we investigated the perception of medical and para-medical students about FGS, as well as the expertise of health care professionals in Anambra State, Nigeria. METHODOLOGY: We conducted a cross-sectional survey among 587 female medical and para-medical university students (MPMS), and 65 health care professionals (HCPs) saddled with the responsibility of delivering care for schistosomiasis-affected persons. Pretested questionnaires were administered to document the awareness and knowledge about the disease. In addition, the expertise of HCPs vis-à-vis suspicion of FGS and management of FGS patients during routine health care service were documented. Data were subjected to descriptive, chi-square tests and regression analysis in R software. RESULTS: Over half of the students recruited; 54.2% for schistosomiasis and 58.1% for FGS, were not aware of the disease. Knowledge about schistosomiasis was associated with student's year of study, with those in 2nd (OR: 1.66, 95% CI: 1.0, 2.7), 4th (OR: 1.97, 95% CI: 1.2, 3.2), and 6th (OR: 5.05, 95% CI: 1.2, 34.2) year having higher likelihoods of been more informed about schistosomiasis. For HCPs, we observed a contrastingly high knowledge about schistosomiasis (96.9%), but low knowledge about FGS (61.9%). Knowledge for both schistosomiasis and FGS was not associated with year of practice and expertise (95% OR included 1, p > 0.05). A considerable proportion (>40%) of the HCPs never suspected schistosomiasis during routine clinical diagnosis of patients who presented probable FGS symptoms (p < 0.05). Similarly, only 20% were certain about the use of praziquantel for treating FGS, and about 35% were uncertain of the eligibility criteria and dosage regimens. Commodities for managing FGS were also largely unavailable in about 39% of the health facilities where the HCPs operate. CONCLUSION: Awareness and knowledge about FGS among MPMS and HCPs were poor in Anambra, Nigeria. It is therefore important to invest in innovative methods of building capacity of MPMS and HCPs, with complementary provision of necessary diagnostics to perform colposcopy, as well as competence to diagnose pathognomonic lesions using diagnostic atlas or Artificial Intelligence (AI).

Integrated transmission assessment surveys (iTAS) of lymphatic filariasis and onchocerciasis in Cross River, Taraba and Yobe States, Nigeria.

BACKGROUND: Integrated transmission assessment surveys (iTAS) have been recommended for evaluation of the transmission of both lymphatic filariasis (LF) and onchocerciasis as the prevalence of both diseases moves toward their respective elimination targets in Nigeria. Therefore, we conducted an iTAS between May and December 2017 in five local government areas (LGAs), also known as implementation units (IUs), in states of Cross River, Taraba and Yobe in Nigeria. METHODS: The TAS comprised two phases: the Pre-iTAS and the iTAS itself. Three states (Cross River, Taraba and Yobe), comprising five LGAs and 20 communities that have completed five rounds of combined treatment with ivermectin and albendazole for LF and 12 total rounds of ivermectin, were selected for inclusion in the study. All participants were tested with the Filariasis Test Strip (FTS; Alere Inc.) and the Biplex rapid Diagnostic Test (RDT; identifying filaria antigens Ov16/Wb123; Abbott diagnosctics Korea Inc.). Pre iTAS included 100 children ages 5-9 in each 4 communities and 300 individuals ages 10 and older in a subset of two communities.  For the iTAS, only LGAs where antigenemia prevalence in all sampled communities during the Pre-iTAS was < 2% for LF were selected. RESULTS: Of the five LGAs included in the study, four met the cutoff of the Pre-iTAS and were included in the iTAS; the Ikom LGA was excluded from the iTAS due to antigenemia prevalence. A total of 11,531 school-aged children from 148 schools were tested for LF and onchocerciasis across these four LGAs, including 2873 children in Bade, 2622 children in Bekwara, 3026 children in Gashaka and 3010 children in Karim Lamido. Using the FTS, all samples from Bade and Karim Lamido were negative, whereas 0.2% of the samples from Bekwara and Gashaka were positive. Using the Biplex RDT, LF prevalence in Bade, Bekwara, Gashaka and Karim Lamido was < 0.1%, 0.5%, 0.4% and < 0.1%, respectively. Moreover, all samples from Bade and Karim Lamido were negative for onchocerciasis, whereas 3.1% and 1.8% of the samples from Bekwara and Gashaka were positive, respectively. CONCLUSION: This study has provided additional information on the current burden of onchocerciasis and LF in the four IUs sampled where mass drug administration (MDA) for both infections has been ongoing for years. The study identifies that LF-MDA can be safely stopped in all four of the IUs studied, but that MDA for onchocerciasis needs to continue, even though this may pose a challenge for LF surveillance. Based on the preliminary results from all four sites, this study has fulfilled the primary objective of determining the programmatic feasibility of an iTAS as a tool to simultaneously assess onchocerciasis and LF prevalence in areas co-endemic for the two infections that have completed the recommended treatment for one or both infections, and to make decisions on how to proceed.

Black flies and Onchocerciasis: Knowledge, attitude and practices among inhabitants of Alabameta, Osun State, Southwestern, Nigeria.

BACKGROUND AND OBJECTIVES: This study reports knowledge of residents of Alabameta community, Osun State, Nigeria on the bioecology and socio-economic burden of black flies and onchocerciasis. METHODS: Using structured questionnaires and Focus Group Discussion (FGD), a total of 150 community respondents participated in the study. RESULTS: The knowledge of the residents on the existence of black flies in the community was significant (p<0.05) as all the 150 respondents confirmed the presence of black flies with the local name 'Amukuru' i.e causing itching. However, their lack of knowledge of the flies breeding site (104) (69%), prevention (134) (89%), cause (132) (88%), and treatment (133) (89%) of onchocerciasis was profound. Majority 147(98%) of the respondents reported that flies bite more in the wet season as against dry season 3(2%) and have a higher affinity (124) (82%) for biting the leg than any other part of the body. A larger percentage (89%) of the respondents are unaware of any medication for the treatment of onchocerciasis while 11% are aware. There had been no sensitization on onchocerciasis according to 89% of the respondents. CONCLUSION: Due to lack of resident's knowledge on black flies bioecology which may continuously expose them to the bite of the flies and ultimately infection, it is paramount that the Osun State government and the NTD implementing partner map out new public health education strategies during routine Mass Administration of Medicines with Ivermectin with a view to preventing onchocerciasis infection as well as man-vector contact.

Biting behaviour and infectivity of Simulium damnosum complex with Onchocerca parasite in Alabameta, Osun State, Southwestern, Nigeria.

A longitudinal study was carried out to investigate species composition, seasonal abundance, parity and transmission potential of Simulium damnosum complex in Alabameta community in Osun State, Southwestern, Nigeria. Adult Simulium damnosum complex were collected along Owena River, Alabameta, by two dark complexioned vector collectors from 07:00hr to 18:00hr weekly using collecting tubes from November 2014 to April 2015. The flies were morphologically identified and dissected for the purpose of detecting Onchocerca parasite using dissecting microscope. The Monthly Biting Rate (MBR) of flies was determined using World Health Organization standard formula. A total of four hundred and forty flies were collected during the study period with all of them identified as forest species of Simulium damnosum complex. There was significant variation in monthly collection of the flies with the month of November having the highest number of flies (194) (44%) while the month of April recorded the lowest number of flies (31) (7%) (p<0.05). The morning biting peak (09hr - 11hr) (137) was higher than the evening biting peak (15hr -17hr) (64) (p<0.05) while nulliparous flies (294) (67%) were more abundant than the parous flies (146) (33%) (p<0.05). There was absence of infection (zero infectivity) of the flies (p<0.05). The zero infectivity in the flies may plausibly indicate the possibility of zero transmission of Onchocerca parasite in the community which if sustained over a period of time may signify the possibility of onchocerciasis elimination. Also, the presence of forest species of the flies reduces the risk of resident's intense exposure to blinding savannah strain of onchocerciasis.

Notes on distribution of Simulium damnosum s. l. along Atbara River in Galabat sub-focus, eastern Sudan.

BACKGROUND: Onchocerciasis is caused by a nematode worm Onchocerca volvulus, which is transmitted in Sudan by black fly vectors of the Simulium damnosum sensu lato species complex. In Sudan, the disease is found in four foci where fast flowing rivers provide suitable breeding sites for the Simulium vector flies. The construction of dams and irrigation schemes for agricultural purposes has affected black fly breeding and distribution, such as in Merowe Dam in Abu-Hamed focus, where the perennially flowing water downstream of the Dam created new vector breeding sites, thereby, changing the pattern of disease transmission and creating public health problems. Based on this situation, this study was carried out to measure the effect of the Upper Atbara and Setit Dam complex on the distribution of Simulium damnosum s.l. breeding sites and on disease elimination in the Galabat sub-focus in eastern Sudan. METHODS: Aquatic stages of Simulium were collected between October and November 2009, prior to the construction of the dam complex, and again in 2013 and 2015 while the dam complex construction was ongoing. RESULTS: A total of 40 breeding sites were identified at the beginning of the study. After the construction of the dam complex in 2015, seventeen previously mapped breeding sites were inaccessible as they had been flooded by the dam complex's lake when reach its maximum size. Three species were obtained from different locations: S. damnosum s.l., S. griseicolle, and S. adersi. CONCLUSIONS: This study has shown a link between the construction of the dam complex and a reduction in the breeding sites of black fly vectors. This reduction has limited the Galabat sub-focus to a small area at the upper Atbara River which become the end of the focus. To sustain the success achieved in onchocerciasis control in the Galabat sub-focus, disease control and its vector control should be strengthened in the area cross-boarding Sudan and Ethiopia.

Assessment of community knowledge and participation in onchocerciasis programme, challenges in ivermectin drug delivery, distribution and non-compliance in Ogun State, southwest Nigeria.

BACKGROUND: This study reports knowledge of onchocerciasis and surrounding factors from the perspective of community members, Community drug distributors and health workers in eight endemic LGAs of Ogun State, Nigeria. METHODS: Using structured questionnaires and Focus Group Discussion, a total of 417 community members, 37 health workers and 42 CDDs across 16 communities participated in the study. RESULTS: Majority (70.7%) of participants knew the disease by its local name, "Inarun". Community members (62%) identified severe itching as a symptom of the disease while (35.9%) (17.6%) and (9.8%) of participants associated bites of black-flies, physical-exertion on farm and allergies to peanuts as the cause of the disease. Majority (62.2%) of health workers reported the insufficiency of drug-storage facilities at community-health centres. Drug distributors also decried the paucity of funds to facilitate wide therapeutic-coverage. Compliance with drug use was affected by adverse reaction by (4%) Community members, pregnancy (9%) and inability to swallow pills (11.6%). CONCLUSION: To improve onchocerciasis control in Ogun State, public-health-education regarding the disease aetiology needs to be improved. Also, treatment rounds need to be increased to accommodate members who unwillingly missed treatment. Finally, government provision of transport logistics to CDDs for ease of logistics is very important.

Comparative repellent activities of some plant extracts against Simulium damnosum complex.

The root and leaf extracts of four plants, Occimum gratissimum, Azadirachta indica, Pterocarpus santalinoides, and Pistia hyptis, were studied for repellent activities against the adults of Simulium damnosum sensu lato. The leaves and roots were extracted with 95% ethanol and the stocks were diluted with paraffin. The repellent activities of the extracts were investigated using human baits along the banks of River Oyan and River Ogun in southwestern Nigeria. The results showed that the root extract of O. grattissium and leaf extract of P. hyptis had highest repellent potentials with 78% and 78.1% protection against S. damnosum sensu lato, respectively, whereas the root and leaf of P. santalinoides recorded the least. Although there were significant differences in the percentage of protection of the extracts of the plants (p < 0.05), the variations in the percentage of protection of the leaf and root extracts were not statistically significant (p > 0.05). The study concludes that there exist some repellent efficacies in the extracts of the plants, most importantly O. grattissimum and P. hyptis. The plant extracts can further be developed in the prevention of man-vector contact in onchocerciasis endemic communities.