Identification of enteroviruses along Lake Victoria shoreline - a potential indicator of sewage pollution.

Abstract

E n t e r i c v i r u s e s a r e m a i n l y t r a n s m i t t e d b y t h e f a e c a l - o r a l r o u t e a n d h a v e b e e n l i n k e d t o s e v e r a l d i s e a s e s i n c l u d i n g g a s t r o e n t e r i t i s a n d r e s p i r a t o r y i n f e c t i o n s . T h e i r p r e s e n c e i n s u r f a c e w a t e r s h a s b e e n exacerbated by p o l l u t i o n f r o m a v a r i e t y o f p o i n t s o u r c e s s u c h a s s e w a g e d i s c h a r g e . W e s t u d i e d t h e occurrence o f e n t e r o v i r u s e s i n w a t e r s a m p l e s f r o m L a k e V i c t o r i a i n K e n y a t o i n v e s t i g a t e i f t h e r e w a s a l i n k b e t w e e n s e w a g e p o l l u t i o n a n d d e t e c t i o n o f e n t e r o v i r u s e s ( E V s ) t o b u i l d a b a s e l i n e f o r a n enteric viruses monitoring platform for this region. We analysed 216 samples collected over 6 months from six different locations along the Homa Bay Pier. The six sampling locations comprised of three sites (P3, P5, P6) located <500 m from a local sewage treatment plant and pit latrines while three other sites (P1, P2, P4) were located at approximately 0.5 to 3 Km. EVs were concentrated using glass wool adsorption elution protocol and identified using the nested reverse transcription-polymerase chain reaction. The odds ratio was performed to determine whether the location of the sources of sewage pollution near the lake was associated with the EVs contamination. Five out of 108 (5 %) samples collected from the sites (P3, P5 and P6 were EV positive, while 2 % (2/108) of samples from P1, P2 and P4 were EV positive. The presence of the EVs was associated with the distance from the possible sources of faecal contamination (odds ratio 20.28 and 4.86, confidence interval 2.42, and 0.95) for pit latrines and the sewage treatment plant respectively. The result from this study indicates that sewage discharge at the shoreline of Lake Victoria may have been the source of EVs contamination. Data from this study could significantly contribute to informing risk management on sewage pollution in Lake Victoria and it is important to continue monitoring this lake for potentially pathogenic enteric viruses.