In the South West Region of Cameroon, reports on urogenital schistosomiasis are mostly from rural areas [7, 19–22]. Nevertheless, increased risk of schistosomiasis in peri-urban and urban towns is not uncommon. In 2018, an unmapped UGS transmission focus was observed in Tiko, a semi urban town in the THD in the Mount Cameroon area . The current study reveals that UGS varied significantly among Has as well as communities. Proximity to stream, intense water contact and inaccessibility to improved water sources are important drivers of transmission of S. haematobium in the district.
Our study confirms that, there is S. haematobium transmission in three (Likomba, Holforth-Likomba and Holforth) out of the four health areas surveyed in the THD with the occurrence of infection at 31.5%. Overall, this prevalence places THD under the WHO classification of moderate risk communities . Comparatively, lower prevalence rates have been observed in some urban and semi-urban settings in other Regions of Cameroon: 1.7% in Kékem  and 22.9% in Maroua . These areas are targeted regularly for control of schistosomiasis and geohelminths and may account for the lower prevalence of schistosomiasis in these areas . The occurrence of S. haematobium in THD may due partly to the presence and use of many fresh waterbodies (Moungo River) and its tributaries including several streams (Ndongo), which intersperse the Mount Cameroon Area. Another factor may be because the streams are in proximity to residential areas, which suggests frequent contact with water through swimming, bathing, fishing, farming, and laundry. The Mutengene HA had zero prevalence. Infrequent contact with water bodies, probably due to the far distance to water body, may account for the absence of infection in this HA (Fig. 5). The influence of topography on Schistosoma parasite transmission has been emphasized . Mutengene is located at a higher altitude (220 m above sea level) with a hilly topographic terrain characterized by fast flow of the “Ndongo” stream which slows as it flows across the Tiko and Limbe towns. Similarly, Adie et al.  in Nigeria reported absence of schistosomiasis in communities located at higher altitudes. Conversely, lower altitudes could have a significant impact on the Schistosoma snail vector distributions, which are likely to be more concentrated in areas where there is a slow water current . This may explain the predominance of UGS in the Holforth and Likomba Health Areas located at a lower altitude (18–80 m asl).
Among the nine affected communities, five namely; LK-UC/MC; HOL-LKQ1,2,3; HOL-LKQ4,5,6; HOL-LKQ 8,9 and HOLQ6 had infection > 31% with HOL-LKQ 1,2,3 (52%) and HOL-LKQ4 (56.9%) observed as high-risk communities (> 50%). This may be because most people in these communities live very close to the stream (> 80%) and are involved in intense contact with surface water. On the other hand, communities like HOL Q2 (92%; 12.5%) and HOL Q6 (83%; 17%), where most of the people live far (≥ 100 m) from open water surface, have access to alternative improved water sources such as protected wells and boreholes had low prevalence of infection . This study strongly demonstrates the local transmission of schistosomiasis which suggests focus attention in the control of this disease. The maps obtained provide information about areas where studies and control efforts need to be focused. Preventive chemotherapy with praziquantel should be immediately put in place to reduce morbidity and interrupt transmission. Nevertheless, a malacological study on the distribution of snail intermediate hosts is crucial to elucidate the epidemiology of infection in the Health Areas in the THD.
The prevalence of S. haematobium decreased with age where school-aged children (5–14 years) were associated with increased odds and intensity of S. haematobium infection. This agrees with trends established in surveys carried out in Cameroon [20, 38] and other parts of Africa [17, 39]. Children are the most infected group of people in endemic areas, thus contributing significantly to the potential contamination of the aquatic environment . Individuals of this age group are predisposed to schistosome infections due to their active life; hence increased water contact activities with cercaria infested streams . Age-acquired immunity to reinfection contributes to declining trend in infection prevalence with increasing age .
The education level of the inhabitants was also strongly associated with the transmission of S. haematobium. Contrary to findings by Wepnje et al.  in Munyenge, Mount Cameroon Area, secondary level of education increased the odds of infection when compared to primary level of education. There is no distinct reason why individuals with secondary education had higher prevalence of infection. However, from statistical analysis, it is reasonable to suggest that the active age group (11–24 years) may fall more into the secondary education category.
Afiukwa et al.  suggested that 11–20 age group is the most active age group frequently engaging in activities that bring them in contact with infested water bodies. The sex dependent pattern of schistosome infections is widely reported . Conversely, the prevalence of infection in males and females was similar. It is likely that, socioeconomic conditions, and habits in the THD could modify sex-biased tendencies to participate in activities that predispose to infection with S. haematobium [17, 37]. Males and females equally participate in activities such as bathing, swimming, and washing in streams, which served as major predisposing factors. Similar observations were made in previous studies in Nigeria , Cote d’Ivoire  and Cameroon .
Despite the presence of improved water facilities in the Health Areas, about 50% of the population visit the stream daily and one-third of those who use the stream, engage in two or more water-related activities. In most countries where schistosomiasis is endemic, inadequate access to clean water sources is major concern . Distance from home, limited number of communal piped-borne water sources and requirement for immediate payment of piped-borne water are leading causes for limited access to water [42, 46]. Natural water bodies, many of which are infested with snails and infective schistosome cercariae, are common sources for domestic water in most schistosomiasis endemic areas . The flow of pipe-borne water in THD is inconsistent, consequently, open water bodies such as streams and springs are common sources of water for majority of the people in this District. Usually people become infected with schistosomes when they make contact with infested water and cercariae penetrate the skin. Schistosome eggs are then excreted in human faeces or urine and when they get into water bodies, miracidia which are released from the eggs in turn infect the snails, which release cercariae which penetrate human skin . The high dependence of the population on natural water bodies avails each water contact activity a potential risk factor of S. haematobium infection . Intense water contact activity and daily visitation to stream (degree II) was associated with increased risk and intensity of S. haematobium infection in THD. This confirms previous reports in other endemic foci in Cameroon [7, 42, 50] and elsewhere . Water contact at any point in time is linked mostly to practices including domestic activities and bathing. Laundry, bathing, and recreational swimming are the activities that cause the most exposure to cercaria-infested water because these do involve the immersion of large body parts, for long periods .