An international team of researchers reports that some people in Bangladesh are concurrently infected with multiple strains of simian foamy virus (SFV), including strains from more than one source (recombinant) that researchers originally detected in the monkeys. By analyzing what is happening at the human/nonhuman primate (NHP) interface, the investigators hope to protect humans from another deadly outbreak like HIV.
Throughout Asia, humans and monkeys live side by side in many urban areas. The scientists, from the University of Washington, Fred Hutchinson Cancer Research Center and Jahangirnagar University, have focused on Asia because it is a continent that has witnessed the emergence of several infectious diseases in the past decade.
Their paper, “Zoonotic simian foamy virus in Bangladesh reflects diverse patterns of transmission and co-infection,” published today in Emerging Microbes and Infections (EMI), characterizes the simian retroviral strains that are being zoonotically transmitted and provides a glimpse into the behaviors of humans and monkeys contributing to the infections.
“In Asia, SFV is likely transmitted to humans through macaque bites and scratches that occur in the context of everyday life,” said the researchers in the EMI paper. “We analyzed multiple proviral sequences from the SFV gag gene from both humans and macaques in order to characterize retroviral transmission at the human/NHP interface in Bangladesh….We report evidence that humans can be concurrently infected with multiple SFV strains, with some individuals infected by both an autochthonous SFV strain as well as a strain similar to SFV found in macaques from another geographic area.”
Since more humans have been shown to have been infected with SFV through primate contact than with any other simian-borne virus, the researchers reason that pinpointing the factors that influence SFV transmission and infection are important to a general understanding of how viruses can jump the species barrier.
“If we want to understand how, where, and why these primate viruses are being transmitted, we need to be looking at SFV in Asia where millions of people and tens of thousands of macaques are interacting everyday and where we estimate that thousands of people could be infected with strains of SFV,” said Lisa Jones-Engel, Ph.D., a primatologist with the National Primate Research Center at the University of Washington and the project leader.
She added that if researchers had been on the ground 50 years ago, they may have seen how simian immunodeficiency viruses (SIV) crossed the species barrier resulting in HIV.
Although SFV is currently not known to be pathogenic, this was also the case for SIV before recombination and mutation allowed infection of and transmission between new hosts, noted Maxine Linial, Ph.D., a retrovirologist at the Fred Hutchinson Cancer Research Center.
“The possibility that a pathogenic SFV strain could arise makes it essential to monitor natural infections,” she added. “If a viral strain with pathogenic potential arises, we will know about it early rather than too late, which was the situation with the emergence of HIV.”