Background: Onchocerciasis control strategies have focused on mass drug administration (MDA) to reduce morbidity in high-risk (HR) areas (sites close to blackfly breeding sites). However, with the current drive towards elimination, treatment must be extended to low-risk (LR) areas. It is uncertain how well HR and LR communities are connected for decision making in recommending treatment strategies to include the LR areas. We provided data on current onchocerciasis infection status, connectivity between HR and LR communities and rates of human movement within some endemic communities in Ghana. Methods: Selected communities were 5km (HR) and 15km (LR) from breeding sites. Questionnaires were administered to obtain data on demographics and human movement patterns. Samples were collected from participants and tested for O. volvulus infections using Ov16 RDT and presence of microfilariae (mf) in skin snips using microscopy and quantitative PCR. Results: We observed a significantly higher onchocerciasis prevalence in HR than LR sites for both sero-prevalence (42.5% vrs 16.0%) and mf prevalence (15.2% vrs 4.1%) [ P < 0.0001]. There was a high connectivity between the HR and LR with about 64–82% people who moved from HR to LR and 3.2-10% from LR to HR daily or weekly. Infection levels in those who moved from HR to LR communities were higher than those who moved from LR to HR, although these were not statistically significant ( P > 0.05). Some individuals in Lancha (a LR community) who tested positive for infection frequently visited the HR communities for farming. Conclusions: A strong connectivity existed between HR and LR communities by human movement. On the average >60% of participants moved between endemic communities (between HR and LR) either daily, within the week or weekly. This supports the need to initiate treatment in LR areas; hence, such movement data would be useful during assessment of onchocerciasis elimination and delineation of transmission zones.

Background: Recently, arboviruses have been of concern as pathogens for emerging and re-emerging infectious diseases. In Ghana, yellow fever outbreak occurred in Savannah Region in the year 2021. A team from different institutions, organisations, and stakeholders of health with varying vital expertise was assembled to respond to this national emergency to assess, contain and/or control the rapid spread of the disease. This paper presents findings from the entomological investigations conducted during the yellow fever outbreak. Methods: Immature stages of Aedes mosquitoes were collected from breeding containers in and around houses, and adult mosquitoes sampled using BG-Sentinel traps, human landing catches and Prokopack collections. After morphological identification of these mosquitoes, they were screened for Chikungunya, Dengue Fever, Yellow Fever, and Zika viruses using real time reverse-transcription polymerase chain reaction. Results: In all, 12,264 breeding containers were examined. A total of 3,885 larvae and 1,186 pupae were obtained from 173 containers. Out of 1,001 houses surveyed, 130 were positive for larvae and/or pupae. The breeding receptacles included plastic (6,529), metallic (6,024), clay jar (753), tire (565), and well (34). The WHO thresholds for arboviruses larval indices were used to assess risk. A total of 1571 adults identified [ Aedes aegypti aegypti (35), Aedes aegypti formosus (619), and Culex (917)] were collected with adult mosquito sampling methods or emerged from immature mosquitoes stages. None of the arboviruses were detected using qPCR. Conclusion: Vectors had no yellow fever infections. There was a high risk of arbovirus transmission in the study areas although mosquito vectors were not positive for arboviruses. Aedes aegypti formosus was the dominant Aedes species. They might be drivers for yellow fever transmission during outbreak. Generally, arboviral transmission was high in all study districts. Although yellow fever virus was not detected, Aedes aegypti populations and transmission risk in study districts was high. Author summary: In 2021, Savannah Region of Ghana experienced yellow fever outbreak. This spread quickly to adjoining regions. The disease is transmitted by some female mosquitoes infected with yellow fever virus. These same mosquitoes can transmit other viral infections resulting in disease outcomes such as chikungunya, dengue, and zika. A team of experts from stakeholders of health were mobilised to control and/or contain the spread of the disease to other parts of Ghana. The team carried out several activities and assessments to stop the spread of yellow fever. Notably is the investigation to determine different types of mosquitoes involved in transmitting the disease. We collected some mosquitoes and processed them for vital information that could prevent future outbreaks of the aforementioned diseases. There is no surveillance system in Ghana to pick up early warnings regarding potential viral disease outbreaks. Therefore, there is scanty information on these type of mosquitoes and viruses found in different places. We used standard procedures to assess the risk of these mosquitoes in causing future disease outbreaks. Our findings suggested a high risk of future outbreaks for any of the viral diseases tested. We therefore recommended the implementation of a mosquito surveillance system to prevent future outbreaks.

Ghana’s lymphatic filariasis (LF) elimination was intensified by Global Programme to Eliminate Lymphatic filariasis in 2000. LF transmission was interrupted in some endemic district, yet, persistent in others. This study investigated some characteristics of Wuchereria bancrofti that potentially contribute to persistent LF transmission in Ghana’s endemic districts after prolonged mass chemotherapy (≧15yrs) expected to interrupt transmission. Participants’ finger-prick blood was screened for antigenaemia and positives followed for night blood to detect microfilariae. The antigenaemia/microfilaraemia prevalence, implications of W. bancrofti transmission, and microfilariae clearance using scoring method (SM) were assessed. Exactly 2973 individuals were screened for antigenaemia and 33 found positive. Infected individuals were followed for night blood to detect microfilaraemia in 8 communities from the 4 study districts. The antigenaemia/microfilaraemia prevalence in Antseambua, Asemkow, Badunu, Navio (Sanwu) Central, Atampiisi Bongo, and Balungu Nabiisi were 1.3/0.0, 0.8/0.3, 0.8/0.0, 1.2/0.0, 1.7/0.0, and 3.1/0.9 respectively but none in Ampeasem and Obrayebona. Microfilariae density for thick blood films/Sedgwick counts was relatively higher in Western Region (283.9/410.0) compared to Upper East Region (44.5/25.0). Microfilariae clearance/reinfection was observed (using SM). Currently, prevalence thresholds suggest competent vectors can sustain LF transmission in Ahanta West District (hotspot) and cause possible reinfection/resurgence in Bongo (control district).