to be caused by a strain of P. brasilianum with 100% identical to sequences found in Alouatta seniculus monkeys. This suggests a definite zoonosis and high possibility of spillback back into non-human primate bands as reverse zoonoses. African sleeping sickness Trypanosoma brucei gambiense (T. b. gambiense) is a species of African trypanosomes which are protozoan hemoflagellates responsible for trypanosomiasis (more commonly known as African sleeping sickness) in humans and other animals. The protozoa are transferred via Tsetse flies where they multiply and can be transferred to yet another animal host during the fly's blood meal feeding. Outbreaks of sleeping sickness in certain human communities have been eliminated but only temporarily as constant re-introduction from unknown sources statistically suggests the presence of a non-human reservoir where spillback of the pathogen is maintained in a sylvatic cycle and re-introduced into the urban cycle. The presence of T. b. gambiense has been found separately in humans and livestock. This spurred a molecular study comparing serum reactivity of pigs, goats, and cows to human serum where notable similarities in all samples but especially in pig samples. Combined, these findings implicate a reverse zoonotic human to animal transmission. Arboviruses Yellow fever viruses, Dengue fever viruses, and Zika viruses are of the Flavivirus genera and Chikungunya virus is of the Alphavirus genera. All of them are considered arboviruses denoting their ability to be transmitted through arthropod vectors. Sylvatic transmission cycles for arboviruses within non-human primate communities have the potential to spillover into an urban cycle within humans where humans could be dead-end hosts in scenarios where further intermingling is eliminated but much more probable is a reemergence of these viruses into either cycle due to spillback. Apparently the maintenance of an arboviral urban cycle between humans requires a rare or understudied conjunction of factors to occur. One of the following situations occurs: An infected human in an urban environment feeds a sylvatic (typically remotely located) mosquito such as Haemogogus (which has a relatively long lifespan compared to other mosquitoes and can transmit the virus for extended periods) that infects another human or non-human animal that will serve as a reservoir. An urban Aedes (more commonly found in urban areas feeds and transmits the virus to another human or non-human animal that will serve as a reservoir. Sufficient numbers of sylvatic vector mosquito and the animal reservoir inhabit the same ecologic niche in close contact to promote