“Vector-borne diseases are among the most complex of all infectious diseases to prevent and control. Not only is it difficult to predict the habits of mosquitoes, ticks, and fleas, but most vector-borne viruses or bacteria infect animals as well as humans,” according to
the Centers for Disease Control and Prevention (CDC). Six officers of the CDC’s Epidemic Intelligence Service (EIS) presented their recent research findings on May 3 in the Vectorborne Diseases session of the 65th Annual Epidemic Intelligence Service (EIS) Conference in Atlanta, Georgia. A summary of the presentations is included below:
The chikungunya virus (CHIKV), transmitted by mosquitoes, emerged in the United States Virgin Islands (USVI) in June 2014, and that same year, 380 locally transmitted and 19 travel-associated cases were reported.
Over one week in February 2015, Cara C. Cherry, DVM, MPH,
and her colleagues surveyed Virgin Islands National Park visitors 18 years of age and above at 10 park locations with a questionnaire assessing their CHIKV knowledge, attitudes, and health information-seeking practices, as well as their travel details and demographics.
Of the 443 people who completed the survey, 208 (47%) were aware of CHIKV. During trip preparation, 126 (28%) of them investigated USVI-specific health concerns, and 102 of the 126 (81%) were aware of CHIKV. Visitors who were aware of CHIKV were more likely to apply insect repellent ([134 of 207; 65%] vs [111 of 231; 48%]; P
<0.001), wear long pants and long-sleeved shirts ([84 of 203; 41%] vs [57 of 227; 25%]; P
<0.001), and wear clothing treated with insect repellent ([36 of 204; 18%] vs [22 of 227; 10%]; P
Based on their findings, the authors advised that tourists need to be educated about their travel-related CHIKV risks.
Jefferson M. Jones, MD, MPH,
and his co-authors detected no locally acquired Dengue virus (DENV) cases along the border of Yuma County, Arizona and Sonora, Mexico; but their entomologic findings and the frequent border crossings during Dengue outbreaks make Dengue possible to occur in Yuma County.
From September through December 2014, during a Dengue epidemic in Sonora caused by Aedes
species mosquitoes, 95 travel-associated Dengue cases were reported in Arizona. Seventy-five percent of the cases were among Yuma County residents. The researchers investigated households within 50 meters of patients’ Yuma County residences. All residents within that area were offered a questionnaire and Dengue diagnostic testing by reverse transcription polymerase chain reaction (RT-PCR) and anti-DENV IgM Enzyme-Linked Immunosorbent Assay (ELISA). In addition, their houses and yards were tested for mosquito breeding sites.
Of the 194 participants in 113 households, four participants had traveled to Mexico within the previous three months and had detectable anti-DENV IgM antibody, but none reported a recent febrile illness; 152 (78%) reported travelling to Mexico at least monthly; and 42 (37%) households reported mosquitoes in their home. The researchers advised travelers to avoid contact with mosquitoes and to kill them if possible.