Effects of Deforestation on Avian Parasitic Co-infections in Recaptured Birds from an African Tropical Rainforest

Abstract

The impact of environmental changes due to deforestation that gives rise to the spread of infectious diseases remain insufficiently studied, particularly in parasitic co-infection scenarios. The mark-recapture of birds is of particular interest since we can study human-impacted environments and conduct longitudinal studies of infections. Birds in the South West region of Cameroon were sampled prior to deforestation in 2016 and again in 2017 following deforestation in an area slated for palm oil agriculture. The impact of deforestation on parasitaemia, co-infections trends (of four avian haematozoans and the Superfamily Filarioidea) and the relationships between the prevalence of co-infection of parasites and microclimatic factors (temperature and relative humidity) in all recaptured birds were analyzed using both microscopy and PCR techniques. A total of 1798 birds were caught, 156 of which were recaptures. The three most abundant birds recaptured were Bleda notatus (20.51%), Alethe castanea (18.59%) and Stiphrornis erythrothorax (8.97%). 90.39% of recaptures harbored at least one parasite genus and 81.56% had co-infections. Plasmodium, Trypanosoma and microfilariae parasitaemia, did not change significantly while Haemoproteus and Leucocytozoon parasitaemia varied significantly in particular bird species from first capture to subsequent recapture. Plasmodium exhibited the highest diversity, prevalence and prevalence of co-infection with other avian haematozoans, and differed significantly across both forest types. Random forest analysis revealed that year of sampling, temperature and relative humidity are important predictors of parasitic co-infections. This study recorded fourteen new genetic cytochrome b lineages (10 Plasmodium and 4 Haemoproteus). Our work suggests that of the parasites tested, avian Plasmodium spp. are the best indicators of environmental disturbance because prevalence of infection varied significantly across forest types. Being in the early stages of understanding the complex interactions between avian hematozoa and their hosts in light of rapid environmental change, the study provides baseline information of parasitic co-infection trends in response deforestation.