Current Status of Snail Vectors in Port-Harcourt Metropolis, Rivers State, Nigeria.

Snails act as intermediate hosts and play active role in the transmission of trematodes. Assessments of snail vectors of public health importance in Port-Harcourt metropolis were conducted following previous report on emergence and re-emergence of schistosomiasis; in twelve locations once monthly from January to June 2019. Snails were collected in each water body using scooping net and handpicking method for 45 minutes/location and identified using shell morphology. They were screened for patent infection through exposure to sunlight individually for two hours in a petri-dish that contains clean water and checked for cercarial shedding in the laboratory using a microscope. Physico-chemical parameters (pH, temperature, dissolved oxygen (DO), conductivity, and total dissolved solid (TDS)) of the water bodies were analyzed monthly using standard methods. 1812 freshwater snails were collected and relative abundance recorded was: Lymnaea natalensis 1221(67.38%), Physa sp. 518(28.58%), Indoplanorbis exutus 44(2.42%) and Oncomelania sp. 29(1.60%). The study established the absence of Bulinus sp. in Port Harcourt metropolis and revealed that the density of fresh water snails varied monthly following wet and dry seasons. There was a significant difference in snail abundance in relation to species (F=16.24, p= 0.01 at p<0.05). The difference in snail abundance across habitat was not significant (F=0.525, p= 0.873). DO was the significant parameter influencing abundance of snail host identified. It is concluded that malacological survey is therefore vital for surveillance and effective snail control programme. Keywords: Distribution, Snail vectors, Port-Harcourt Metropoli