West Nile virus (WNV) (Flavivirus: Flaviviridae) is the most widespread arbovirus in the world. A significant range expansion occurred beginning in 1999 when the virus was introduced into New York City. This review highlights recent research into WNV epizootiology and epidemiology, including recent advances in understanding of the host-virus interaction at the molecular, organismal, and ecological levels. Vector control strategies, vaccines, and antivirals, which now must be considered on a global scale, are also discussed.

A Global Perspective on the Epidemiology of West Nile Virus

The potential for transport and dissemination of certain pathogenic microorganisms by migratory birds is of concern. Migratory birds might be involved in dispersal of microorganisms as their biological carriers, mechanical carriers, or as carriers of infected hematophagous ecto- parasites (e.g., ixodid ticks). Many species of microorganisms pathogenic to homeothermic ver- tebrates including humans have been associated with free-living migratory birds. Migratory birds of diverse species can play significant roles in the ecology and circulation of some arboviruses (e.g., eastern and western equine encephalomyelitis and Sindbis alphaviruses, West Nile and St. Louis encephalitis flaviviruses), influenza A virus, Newcastle disease virus, duck plague herpes- virus, Chlamydophila psittaci, Anaplasma phagocytophilum, Borrelia burgdorferi sensu lato, Campylobacter jejuni, Salmonella enterica, Pasteurella multocida, Mycobacterium avium, Candida spp., and avian hematozoans. The efficiency of dispersal of pathogenic microorganisms depends on a wide variety of biotic and abiotic factors affecting the survival of the agent in, or disap- pearance from, a habitat or ecosystem in a new geographic area.

https://bioone.org/journals/journal-of-wildlife-diseases/volume-40/issue-4/0090-3558-40.4.639/AN-ANNOTATED-CHECKLIST-OF-PATHOGENIC-MICROORGANISMS-ASSOCIATED-WITH-MIGRATORY-BIRDS/10.7589/0090-3558-40.4.639.pdf

An annotated checklist of pathogenic microorganisms associated with migratory birds

West Nile virus: epidemiology and ecology in North America.

Japanese encephalitis virus (JEV) (Flavivirus: Flaviviridae) is a leading cause of encephalitis in eastern and southern Asia. The virus is maintained in a zoonotic cycle between ardeid wading birds and/or pigs and Culex mosquitoes. The primary mosquito vector of JEV is Culex tritaeniorhynchus, although species such as Cx. gelidus, Cx. fuscocephala, and Cx. annulirostris are important secondary or regional vectors. Control of JEV is achieved through human and/or swine vaccination, changes in animal husbandry, mosquito control, or a combination of these strategies. This review outlines the ecology of JEV and examines the recent expansion of its geographical range, before assessing its ability to emerge in new regions, using the hypothetical establishment in the United States as a case study.

Ecology and Geographical Expansion of Japanese Encephalitis Virus

West Nile (WN) virus is a mosquito-transmitted flavivirus. It is widely distributed in Africa, the Middle East, Asia, and southern Europe and was recently introduced to North America. Birds are involved in the cycle of transmission as amplifying hosts. Humans and horses are considered accidental dead-end hosts. WN fever was initially considered a minor arbovirosis, usually inducing a nonsymptomatic or a mild flu-like illness in humans, but some cases of encephalitis associated with fatalities were reported in Israel in the 1950s. After two silent decades, several human and equine outbreaks of fatal encephalitis occurred from 1996 to 2000 in Romania, Morocco, Tunisia, Italy, Russia, Israel, and France. In Romania, a few cases of WN encephalitis in humans are noticed every year, and in France, recent WN infections have been detected in monitored sentinel birds in 2001 and 2002. Phylogenetic studies have shown two main lineages of WN strains. Strains from lineage I are present in Africa, India, and Australia and are responsible for the outbreaks in Europe and in the Mediterranean basin, and strains from lineage II have been reported only in sub-Saharan Africa. In 1998, a virulent WN strain from lineage I was identified in dying migrating storks and domestic geese showing clinical symptoms of encephalitis and paralysis in Israel. A nearly identical WN strain suddenly emerged in New York in 1999, killing thousands of native birds and causing fatal cases in humans. The virus is now well established in the New World, and it disseminates rapidly. New modes of transmission through blood donations, organ transplants, and the intrauterine route have been reported. In Europe, an enhanced surveillance of WN infection in humans, horses, birds, and vectors may reveal the presence of the virus in different locations. Nevertheless, outbreaks of WN virus remain unpredictable. Further coordinated studies are needed for a better understanding of the ecology and the pathogenicity of the WN virus.

West Nile Virus: An Overview of Its Spread in Europe and the Mediterranean Basin in Contrast to Its Spread in the Americas

We report West Nile virus (WNV) activity in the Dominican Republic for the first time. Specific anti-WNV antibodies were detected in 5 (15%) of 33 resident birds sampled at one location in November 2002. One seropositive bird was <4 months old, indicating a recent infection.

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West Nile virus transmission in resident birds, Dominican Republic.

We report West Nile virus (WNV) activity from a new area on Hispaniola, in the vicinity of Monte Cristi National Park in northwest Dominican Republic. Specific anti-WNV antibodies were detected in 12 of 58 (21%) resident birds sampled in March 2003, representing six species in the orders Cuculiformes (cuckoos), Strigiformes (owls), and Passeriformes (song birds). This seroprevalence is the highest reported from any site in the Caribbean Basin. Virus was not detected in any mosquitoes or tissues from bird specimens. Testing of 20 sick or dead birds was negative for WNV. Undetermined flavivirus antibodies were detected in four resident birds at Monte Cristi, as well as in five resident birds at Sierra de Baoruco National Park in southwest Dominican Republic. These data suggest that an unidentified flavivirus, as well as WNV, is active in the Dominican Republic.

West Nile Virus Survey of Birds and Mosquitoes in the Dominican Republic

The seasonal prevalence and container preferences of Aedes albopictus (Skuse) were studied in the park, Parque Mirador del Norte in Santo Domingo City, Dominican Republic, from January to December 1994. Tire ovitraps were set along a transect through the park and monitored weekly while two larval surveys were conducted in both the park and surrounding houses using standard entomological methodology. No seasonal pattern of oviposition was observed with similar numbers of positive tire traps collected in the wet and dry season. Most of the positive ovitraps were located in the middle of the park. Within ovitraps , Aedes aegypti (L.), Ae. albopictus, Culex corniger (Theobald), Ochlerotatus albonotatus (Coquillett), and Toxorhynchites sp. were collected. The larval surveys found 7 associated mosquito species, including Ae. aegypti, Ae. albopictus, Ochleotatus mediovittatus (Coquillett), Anopheles albimanus (Weidemann), Culex nigripalpus (Theobald), and Culex quinquefasciatus Say. The Ae. albopictus breeding sites were plastic buckets (4), rock holes (3), and Styrofoam lunch containers (3). We suggest that further studies should be conducted to determine its geographic distribution and vector potential in the

Seasonal prevalence and container preferences of Aedes albopictus in Santo Domingo City, Dominican Republic.

Keyword Index: Aedes albopictus, tire trap description, surveillance tool, Dominican Republic. With the introduction of Aedes albopictus (Skuse) into the Americas from southeast Asia and Japan (Hawley 1988), many surveillance tools originally used for Aedes aegypti Linn. programs were adopted to monitor the new invading species. In the continental U.S.A., conventional ovitraps (Fay and Eliason 1966) and modified ovitraps using seed germination paper substrates (Steinly et al. 1991) have been used for collecting eggs. However, tire casing traps were used for collecting aquatic immature stages (Niebylski and Craig 1994) while the New Jersey Light traps, CDC light traps, Duplex cone, Bi-directional Fay and Omni-directional traps were used for collecting adult Ae. albopictus (Jensen et al. 1994, Crans et al.1996). In the rest of the Americas, tire surveys (larval surveys) and ovitraps have been used in Mexico (IbañezBernal and Martínez-Campos 1994), larvitraps in Cuba (Broche and Borja 1999), larval surveys in Guatemala (Ogata and Lopez-Samoyoa 1996), and larval surveys in Argentina (Rossi et al. 1999) have been used to monitor the immature stages of the invading populations of Ae. albopictus. In the Dominican Republic, Ae. albopictus was first discovered in 1993 (Pena 1993). To monitor their infestation level, we used a motor bicycle tire trap that exploited the mosquito preference for used tires. This paper describes a modified tire trap device developed to monitor the oviposition behavior of Ae. albopictus and facilitate the inspection and collection of immature stages in the field.

Guillermo Gonzalvez

Papers

West Nile virus transmission in resident birds, Dominican Republic.

West Nile Virus Survey of Birds and Mosquitoes in the Dominican Republic

Seasonal prevalence and container preferences of Aedes albopictus in Santo Domingo City, Dominican Republic.

A modified tire ovitrap for monitoring Aedes albopictus in the field