In September 2015, the first reported case of Mayaro virus was identified in Haiti, marking the first case of the virus to be reported outside of South America. The case, an eight-year-old boy, was concurrently diagnosed with dengue fever. The boy attends a Haitian school that works in partnership with researchers at the University of Florida (UF) to collect blood samples of students that present acute undifferentiated febrile illness, in order to study the transmission of chikungunya in Haiti. The student was initially diagnosed with typhoid based on his symptoms of a fever and abdominal pain, and was treated with the antibiotic co-trimoxazole. The UF researchers tested his blood and it was found to be negative for chikungunya, but positive for dengue virus. When culturing the strain of dengue, the cytopathic changes in the cultured cells induced by dengue occurred at a slower rate than what is usually observed, which suggested either a mutation in the strain, or a co-infection. Further analysis of the sample led the researchers to conclude that the student was infected with Mayaro virus in addition to dengue [1].
Mayaro virus was first isolated in Trinidad in 1954 [2]. Sporadic outbreaks have been thought to be largely isolated to the northern region of South America. There is also a suggested presence from serologic survey findings in Central America, as can be seen in Figure A1 from the Centers for Disease Control and Prevention (CDC) [3].
Mayaro virus is in the alphavirus family, among chikungunya virus, dengue virus, and Zika virus. Symptoms of the virus include a febrile illness lasting 3-7 days including chills, headache, nausea, diarrhea, and a maculopapular rash. Additionally, the most notable sign of Mayaro is the debilitating joint pain that can be long lasting (although no permanent damage of the affected areas had been reported thus far) [4]. The virus is transmitted by mosquito, mainly through the Haemogogus genus, which dwell largely in rural settings. However, Mayaro virus has demonstrated vector competence in the Aedes aegypti mosquito, which is also a known vector of chikungunya, yellow fever, and Zika virus, and is found in urban settings [5].
The similarity in clinical symptoms between Mayaro virus and other more prevalent alphaviruses, like chikungunya, means that Mayaro virus is likely underdiagnosed. Based on findings reported by the CDC, Mayaro virus is actively circulating in the Caribbean region, and there may be a link between the strain in Haiti and the strains circulating in Brazil [1]. For now, there is not cause for concern because the Haitian case may be an isolated incident. The case in Haiti, at the very least, should serve as a warning that Mayaro virus must be closely monitored. Proactive surveillance and precautions could help us avoid another Zika-like outbreak.
Sources:
[1] https://wwwnc.cdc.gov/eid/article/22/11/16-1015_article
[2]https://www.ncbi.nlm.nih.gov/pubmed?cmd=Retrieve&db=PubMed&list_uids=13487973&dopt=Abstract
[3] http://wwwnc.cdc.gov/eid/article/18/4/11-1717-fa1
[4] http://wwwnc.cdc.gov/eid/article/18/4/11-1717_article
[5]https://www.ncbi.nlm.nih.gov/pubmed?cmd=Retrieve&db=PubMed&list_uids=21976583&dopt=Abstract
