West Nile Virus Infection in Free-Ranging Squirrels in Illinois

Heinz-Taheny, Kathleen; Andrews, John J.; Kinsel, Michael J.; Pessier, Allan P.; Pinkerton, Marie E.; Lemberger, Karin; Novak, Robert J.; Dizikes, George J.; Edwards, Eric; Komar, Nicholas

doi:10.1177/104063870401600302

Cited by 40 publications

(33 citation statements)

References 14 publications

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“…The absence of gross lesions in symptomatic and asymptomatic WNV-infected gray and/or fox squirrels, and presence of lymphoplasmacytic inflammatory lesions in brain, kidney, and liver tissues are consistent with observations in experimentally infected (Root et al 2006) or naturally infected symptomatic or dead squirrels (Kiupel et al 2003, Heinz-Taheny et al 2004.…”

Section: West Nile Virus and Fox Squirrels 231supporting

confidence: 85%

“…Similarly, Root et al (2006) reported that none of 12 viremic squirrels that were maintained experimentally for 12 days developed symptoms of disease. Symptoms of the affected squirrel were similar to those observed in naturally infected fox and gray squirrels: incoordination, tremors, and varying degrees of paralysis (Kiupel et al 2003, Heinz-Taheny et al 2004, Padgett et al 2007. Although squirrel no.…”

Section: Discussionmentioning

confidence: 59%

“…Heinz-Taheny et al (2004) reported lesions varying from mild to moderate lymphocytic myocarditis to necrotizing myocarditis in 10 of 16 (63%) naturally infected fox and gray squirrels. WNV antigen was demonstrated in heart tissue of 3 of these squirrels.…”

Section: West Nile Virus and Fox Squirrels 231mentioning

confidence: 99%

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Fox Squirrels (Sciurus niger) Develop West Nile Virus Viremias Sufficient for Infecting Select Mosquito Species

Platt

Tucker

Halbur

et al. 2008

Vector-Borne and Zoonotic Diseases

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The West Nile virus (WNV) viremia and shedding profiles of 11 adult fox squirrels (Sciurus niger) infected by needle inoculation or mosquito bite were characterized. Daily mean titers (95% confidence intervals) for all squirrels on days 1 through 6 postexposure (p.e.) were: 10(1.7 (1.32.1)), 10(4.4 (4.04.8)), 10(5.3 (5.05.6)), 10(4.4 (3.94.9)), 10(2.7 (2.03.4)), and 10(1.1 (0.52.1)) plaque-forming units (PFU)/mL. The highest WNV serum titers of individual squirrels infected by needle inoculation or mosquito bite ranged from 10(4.5) to 10(6.1) and from 10(5.1) to 10(5.3) PFU/mL, respectively. Nine (82%) squirrels, including all 4 squirrels infected by mosquito bite, had WNV serum titers > or =10(5.1) PFU/mL that persisted on average for 1.6 +/-0.3 days. Infection and dissemination rates of Culex pipiens (L.) that fed on squirrels with serum titers of 10(4.4 +/-0.1) PFU/mL were 56% and 13%, respectively. Both of these rates increased to over 80% when fed on squirrels with a mean WNV titer of 10(5.5 +/-0.1) PFU/mL. Infection and dissemination also occurred in Aedes triseriatus (Say) but at a much lower rate. WNV was isolated from the oral and rectal cavities of all squirrels and from urine that was opportunistically collected from 5 squirrels. The largest quantity of WNV recovered from swabs of the oral cavity and urine was 10(3.1) PFU. The longest periods after exposure that WNV was isolated from the oral cavity and urine from a squirrel were 22 and 17 days p.e., respectively. WNV RNA was also detected in kidney tissue in 1 squirrel 29 days p.e., suggesting that fox squirrels can be persistently infected. Collectively these observations provide further evidence that squirrels can contribute to the natural history and epidemiology of WNV, especially in peridomestic environments. 1 PFU/mL were 56% and 13%, respectively. Both of these rates increased to over 80% when fed on squirrels with a mean WNV titer of 10 5.5 ؎ 0.1 PFU/mL. Infection and dissemination also occurred in Aedes triseriatus (Say) but at a much lower rate. WNV was isolated from the oral and rectal cavities of all squirrels and from urine that was opportunistically collected from 5 squirrels. The largest quantity of WNV recovered from swabs of the oral cavity and urine was 10 3.1 PFU. The longest periods after exposure that WNV was isolated from the oral cavity and urine from a squirrel were 22 and 17 days p.e., respectively. WNV RNA was also detected in kidney tissue in 1 squirrel 29 days p.e., suggesting that fox squirrels can be persistently infected. Collectively these observations provide further evidence that squirrels can contribute to the natural history and epidemiology of WNV, especially in peridomestic environments.

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Section: West Nile Virus and Fox Squirrels 231supporting

confidence: 85%

Section: Discussionmentioning

confidence: 59%

See 1 more Smart Citation

Fox Squirrels (Sciurus niger) Develop West Nile Virus Viremias Sufficient for Infecting Select Mosquito Species

Platt

Tucker

Halbur

et al. 2008

Vector-Borne and Zoonotic Diseases

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“…In our study, infected mice were euthanized in the acute phase of infection when they began to show clinical signs; as wild prey items, these infected rodents would be relatively easy prey for raptors. The predatory nature of raptors, along with reports of WNV-positive mammals (e.g., Heinz-Taheny et al, 2004), establish the possibility of oral infection in some free-ranging raptors through consumption of infected prey.…”

Section: Discussionmentioning

confidence: 95%

Natural and Experimental West Nile Virus Infection in Five Raptor Species

Nemeth

Gould

Bowen

et al. 2006

Journal of Wildlife Diseases

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120

131

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ABSTRACT:We studied the effects of natural and/or experimental infections of West Nile virus (WNV) in five raptor species from July 2002 to March 2004, including American kestrels (Falco sparverius), golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), barn owls (Tyto alba), and great horned owls (Bubo virginianus). Birds were infected per mosquito bite, per os, or percutaneously by needle. Many experimentally infected birds developed mosquito-infectious levels of viremia (.10 5 WNV plaque forming units per ml serum) within 5 days postinoculation (DPI), and/ or shed virus per os or per cloaca. Infection of organs 15-27 days postinoculation was infrequently detected by virus isolation from spleen, kidney, skin, heart, brain, and eye in convalescent birds. Histopathologic findings varied among species and by method of infection. The most common histopathologic lesions were subacute myocarditis and encephalitis. Several birds had a more acute, severe disease condition represented by arteritis and associated with tissue degeneration and necrosis. This study demonstrates that raptor species vary in their response to WNV infection and that several modes of exposure (e.g., oral) may result in infection. Wildlife managers should recognize that, although many WNV infections are sublethal to raptors, subacute lesions could potentially reduce viability of populations. We recommend that raptor handlers consider raptors as a potential source of WNV contamination due to oral and cloacal shedding.

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“…Mosquitoes are the primary vectors for WNV, and wild birds are the principal hosts (Hubalek and Halouzka, 1999;Campbell et al, 2002;McLean et al, 2002). Evidence of WNV infections in a variety of vertebrates (Steele et al, 2000;Komar et al, 2001;Ludwig et al, 2002;Lichtensteiger et al, 2003;Steinman et al, 2003;Heinz-Taheny et al, 2004) suggests that WNV is widespread in wildlife, and other vertebrate hosts might serve as an overwintering and maintenance reservoir for WNV.…”

mentioning

confidence: 99%