Incursion and establishment of the Old World arbovirus vector Aedes (Fredwardsius) vittatus (Bigot, 1861) in the Americas.

Routine biosurveillance efforts at the Naval Station Guantanamo Bay, Cuba, on 18 June 2019, detected two unusual mosquitos in a CO2-baited CDC light trap. Morphological and molecular analysis confirmed the presence of Aedes (Fredwardsius) vittatus (Bigot, 1861) - the first record of the Old World dengue, chikungunya, Zika and yellow fever virus vector into the Americas - and provides evidence for its establishment in Cuba. Newly submitted GenBank sequences from Dominican Republic further evidence its establishment in the Caribbean, and a median-joining network analysis using mitochondrial COI gene sequences clearly supports multiple introductions of Ae. vittatus into the Caribbean from the Indian subcontinent. It was determined that many Ae. vittatus COI barcode sequences in GenBank are currently misidentified as Aedes (Fredwardsius) cogilli Edwards, 1922.

Multistate Survey of American Dog Ticks (Dermacentor variabilis) for Rickettsia Species.

Dermacentor variabilis, a common human-biting tick found throughout the eastern half and along the west coast of the United States, is a vector of multiple bacterial pathogens. Historically, D. variabilis has been considered a primary vector of Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever. A total of 883 adult D. variabilis, collected between 2012 and 2017 from various locations in 12 states across the United States, were screened for rickettsial DNA. Tick extracts were evaluated using three real-time PCR assays; an R. rickettsii-specific assay, a Rickettsia bellii-specific assay, and a Rickettsia genus-specific assay. Sequencing of ompA gene amplicons generated using a seminested PCR assay was used to determine the rickettsial species present in positive samples not already identified by species-specific real-time assays. A total of 87 (9.9%) tick extracts contained R. bellii DNA and 203 (23%) contained DNA of other rickettsial species, including 47 (5.3%) with Rickettsia montanensis, 11 (1.2%) with Rickettsia amblyommatis, 2 (0.2%) with Rickettsia rhipicephali, and 3 (0.3%) with Rickettsia parkeri. Only 1 (0.1%) tick extract contained DNA of R. rickettsii. These data support multiple other contemporary studies that indicate infrequent detection of R. rickettsii in D. variabilis in North America.

Rickettsia parkeri and Rickettsia montanensis, Kentucky and Tennessee, USA.

We found that 14.3% (15/105) of Amblyomma maculatum and 3.3% (10/299) of Dermacentor variabilis ticks collected at 3 high-use military training sites in west-central Kentucky and northern Tennessee, USA, were infected with Rickettsia parkeri and Rickettsia montanensis, respectively. These findings warrant regional increased public health awareness for rickettsial pathogens and disease.

First records of Aedes japonicus japonicus in Wisconsin.

Aedes japonicus japonicus was collected via gravid trapping in Wisconsin in the summers of 2004 and 2005 at Fort McCoy, Monroe County. Subsequently, in the summer of 2007, Ae. japonicus was captured in a human landing catch in Dane County, Madison, WI. Additional collections were made at this site in the spring of 2008. Invasion is in progress, but significant population increases have not yet been confirmed.

Skin lesions in barracks: consider community-acquired methicillin-resistant Staphylococcus aureus infection instead of spider bites.

Recent outbreaks of mysterious skin lesions on multiple personnel at several military facilities were initially blamed on spiders. Requests were made for pest inspection and control to remedy the situation. Greater scrutiny of the situation led to a hypothesis that instead of spiders, an infectious outbreak of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) should be investigated as the etiology. Subsequent culturing of the lesions on personnel at one facility confirmed this bacterial etiology. Barracks, as well as other close quarter military living conditions, are ripe environments for the establishment, persistence, and spread of CA-MRSA. Military medical personnel should consider CA-MRSA as a more likely etiologic agent than spider bites for cutaneous eruptions in which there are multiple lesions on one person or multiple patients with similar lesions.

A geospatial study of the potential of two exotic species of mosquitoes to impact the epidemiology of West Nile virus in Maryland.

We used geospatial techniques to study the potential impact of 2 exotic mosquitoes, Aedes albopictus and Ochlerotatus japonicus japonicus, on the epidemiology of West Nile virus in Maryland. These 2 species have established populations in Maryland over the past 15 years. Larvae of both mosquito species are found in natural and artificial water-holding cavities and containers, particularly water in tires. Therefore, we used locations of licensed tire dealers and of tire dumps scheduled for clean up as an index for potential sources of mosquito vectors. This index was expected to underestimate the actual population of source habitats. West Nile virus activity in Maryland during 1999, 2000, and 2001 was indicated by the presence of dead, infected birds, particularly American crows and other corvids; infected pools of mosquitoes; and human and horse infections. Adult females of both mosquito species are aggressive, opportunistic feeders that have been observed to take blood meals from avian and mammalian hosts. Susceptible vertebrate hosts, particularly birds, are ubiquitously distributed throughout the developed areas of the state. This analysis demonstrated a spatial convergence of the virus, the exotic mosquito vectors, and susceptible hosts. This conjunction indicated that these 2 mosquito species have a high potential to serve as bridge vectors and thus, impact the epidemiology of West Nile virus under favorable environmental and climatic conditions. Positive mosquito pools were collected from only the Baltimore-Washington metropolitan corridor, suggesting a newly created enzootic focus for this virus. Land-cover analysis of the sites where virus activity had been detected showed predominantly developed land uses. Analyses of the environmental justice aspects (social, economic, and housing characteristics) of block groups with human West Nile fever cases or with positive mosquito pools were equivocal. Human cases seemed to occur in developed block groups with lower income levels.