Prevalence of Neutralizing Antibodies to Rabies Virus in Serum of Seven Species of Insectivorous Bats From Colorado and New Mexico, United States

Abstract

ABSTRACT:We determined the presence of rabies-virus-neutralizing antibodies (RVNA) in serum of 721 insectivorous bats of seven species captured, sampled, and released in Colorado and New Mexico, United States in [2003][2004][2005]. A subsample of 160 bats was tested for rabies-virus RNA in saliva. We sampled little brown bats (Myotis lucifugus) at two maternity roosts in Larimer County, Colorado; big brown bats (Eptesicus fuscus) at three maternity roosts in Morgan County, Colorado; and big brown bats at five maternity roosts in Larimer County. We also sampled hoary bats (Lasiurus cinereus) and silver-haired bats (Lasionycteris noctivagans) captured while drinking or foraging over water in Bernalillo County, New Mexico and at various locations in Larimer County. Big brown bats, little brown bats, long-legged myotis (Myotis volans), long-eared myotis (Myotis evotis), and fringed myotis (Myotis thysanodes) were also sampled over water in Larimer County. All species except long-eared myotis included individuals with RVNA, with prevalences ranging from 7% in adult female silver-haired bats to 32% in adult female hoary bats. None of the bats had detectable rabies-virus RNA in oropharyngeal swabs, including 51 bats of 5 species that had RVNA in serum. Antibody-positive bats were present in nine of the 10 maternity colonies sampled. These data suggest that wild bats are commonly exposed to rabies virus and develop a humoral immune response suggesting some degree of viral replication, but many infections fail to progress to clinical disease.

Bat Rabies in Guatemala

“…Seroprevalence among collection sites ranged from 0 to 21% among all bats, and 0 to 25% for D. rotundus , respectively. Our results are concordant with previous studies in demonstrating that a substantial fraction of apparently healthy bats have detectible rVNA, indicating previous exposure to RABV, and suggesting clearance of peripheral infection without clinical disease [42]–[44]. The presence of rVNA only demonstrates prior exposure to RABV antigens, and does not provide information about the timing, intensity, or frequency of infection [45].…”

“…The detection of rVNA from bats in this study demonstrated RABV exposure among multiple species of bats in Guatemala. The overall rVNA prevalence of 7% was similar to other bat RABV surveillance studies conducted in Peru (10.3%), Grenada (7.6%) and Trinidad (12.8%), but less than the 37% detection in Colima, Mexico [42]–[44]. Seroprevalence among collection sites ranged from 0 to 21% among all bats, and 0 to 25% for D. rotundus , respectively.…”

Variability in Seroprevalence of Rabies Virus Neutralizing Antibodies and Associated Factors in a Colorado Population of Big Brown Bats (Eptesicus fuscus)

“…Oropharyngeal secretions of bats were sampled at the laboratory using cotton-tipped swabs inserted into 0.5 ml of BA-1 medium (Minimal Essential Medium with Hanks’ balanced salt solution containing 0.05 M Tris buffer at pH 7.6, 1% Bovine Serum Albumin, 0.35 g/L of Sodium bicarbonate, 50 mg/L Gentamicin, and 2.5 mg/L Amphotericin B). Serum and oropharyngeal swabs were frozen at −80 C until shipment to the Centers for Disease Control and Prevention (CDC), Atlanta, Georgia for testing [17], [50]. Capture, marking, sampling, and euthanasia of bats were approved by the Institutional Animal Care and Use Committees of Colorado State University and the United States Geological Survey.…”

“…Seroprevalence at other roosts that were sampled only in 2003 are reported elsewhere [50]. We use study numbers for roosts listed in summary statistics, but to protect confidentiality of building owners and occupants we do not provide details of roost locations or names.…”

Rabies surveillance in bats in Northwestern State of São Paulo

“…This result is similar to the 7.4% positivity rate found among hematophagous bats 14 in Botucatu, State of São Paulo, and higher than the 5.9% seroprevalence rate observed in the metropolitan São Paulo region for bats of a variety of species, including hematophagous bats 12 . Serological studies have been conducted in bats and terrestrial wild species in Brazil and other countries as a means of determining the risk of rabies occurrence and the need for RABV surveillance 14,[31][32][33][34][35] . All of these studies detected the presence of RVNAs; although the OIE recommends the standardization of serological techniques for the detection of RVNAs 36 , seroprevalence studies conducted using a variety of methods are still important tools for investigating viral activity levels in wild populations.…”