Human eastern equine encephalitis in Massachusetts: Predictive indicators from mosquitoes collected at 10 long-term trap sites, 1979-2004

State Laboratory Institute, Massachusetts Department of Public Health, Boston, Massachusetts 02130, USA.
The American journal of tropical medicine and hygiene (Impact Factor: 2.7). 03/2007; 76(2):285-92.
Source: PubMed


Human eastern equine encephalitis (EEE) is a life-threatening mosquito-borne disease. To determine whether mosquito abundance and EEE virus infection rates are associated with human EEE disease, we evaluated retrospectively a total of 592,637 mosquitoes and onset dates for 20 confirmed human cases over 26 years in Massachusetts. Annual Culiseta melanura populations at 10 defined sites decreased over the study period (P = 0.002). Weekly infection rates and number of infected Culiseta melanura captured per trap night were positively associated EEE cases (P < 0.023 and P < 0.001, respectively), whereas abundance was not (P = 0.077). The infection rate for Culiseta melanura of 0.39 per 1,000 tested mosquitoes identified human cases with a sensitivity of 0.87, a specificity of 0.82, a positive predictive value of 0.14, and a negative predictive value of 0.995. Timely mosquito testing and infection rate calculation are critical for disease risk estimation and outbreak control efforts.

1 Read
  • Source
    • "Drainage has, particularly in the past, also been used as a source reduction technique for mosquito management. However the research also showed effects such as raised water tables following harvest in some situations, for Wetlands Ecol Manage (2008) 16:255–276 265 example in Cypress and other forested swamps and, incidentally, a habitat of Culiseta melanura (Hachiya et al. 2007). These are very relevent to the creation of, or increase in, mosquito larval habitats, although not surprisingly this is not mentioned in specifically forest-focussed research. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This review brings together information on mosquitoes, the diseases they transmit and the wetlands that provide habitats for the immature stages (eggs and larvae). Wetland values are mentioned, though the main literature on this does not generally overlap the mosquito issue. Mosquito management is overviewed to include: the use of larvicides, source reduction in intertidal wetlands and management in freshwater systems. There is not a great deal of information on mosquitoes and freshwater systems, except for constructed wetlands and they are considered separately. We then consider restoration mainly in the context of wetlands that have been the subject of habitat modification for mosquito control. Land use and climate change, as they affect mosquitoes and the diseases they transmit, are also reviewed, as this will affect wetlands via management activities. Finally the review addresses the critical issue of balancing health, both human and environmental, in an adaptive framework. It concludes that there is a need to ensure that both mosquito and wetland management communicate and integrate to sustain wetland and human health.
    Full-text · Article · Aug 2008 · Wetlands Ecology and Management

  • No preview · Article · Jul 2008 · New England Journal of Medicine
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The incidence of Western Equine Encephalitis (WEE) in humans and equids peaked during the mid-20th century and has declined to fewer than 1-2 human cases annually during the past 20 years. Using the mouse model, changes in WEE virus (WEEV) virulence were investigated as a potential explanation for the decline in the number of cases. Evaluation of 10 WEEV strains representing a variety of isolation locations, hosts, and all decades from the 1940's to the 1990's yielded no evidence of a decline in virulence. These results suggest that ecological factors affecting human and equine exposure should be investigated to explain the decline in WEE.
    Full-text · Article · Oct 2008 · Virology
Show more