Canine Seroprevalence Research Articles

Leishmaniasis eco-epidemiology in the Alpujarra region (Granada province, southern Spain)

An eco-epidemiological study was carried out in the region of the Alpujarras (southern Spain, Granada province). Nine villages were chosen at random in 5 bioclimatic zones. A study of leishmaniasis in the canine and human populations, was carried out concentrating especially upon schoolchildren. A total of 615 dogs were screened, which represents almost 100% of the canine census. Of the screened dogs, 33 showed an antibody titer ≥ 1 160 when tested by IFA (seroprevalence of 5.3%). Age, sex, activity, and clinical symptoms of each dog were taken into account. Among the human population, infection from Leishmania was studied using the Leishmanin skin test (LST). Of 1286 people who were tested, 568 (44.16%) were positive. Most of the subjects were schoolchildren (878; practically 100% of the pupils), of whom 288 (32.8%) tested positive. A close relation was seen to exist between the percentage of positive LST's and age. Finally, a close relationship was also observed between canine seroprevalence and percentage of schoolchildren who tested positive in the LST, in the 5 bioclimatic zones under consideration.

Canine seroprevalence of Rickettsia conorii infection (Mediterranean spotted fever) in Castilla y León (northwest Spain).

A seroepidemiological study was conducted in 308 dogs to determine the presence of antibodies to Rickettsia conorii, using an indirect immunofluorescence assay (IFA). Seven of the provinces of the Castilla y León region (Burgos, León, Palencia, Salamanca, Soria, Valladolid, and Zamora) were covered by the study. Of the 308 dogs analysed, 72 (23.4%) showed significant titers by IFA (1/40 or higher). Seroprevalences were significantly different between provinces of origin of the animals. These were below 30% in almost all the provinces studied, except for Salamanca province, where the percentage of seropositive dogs was much greater (93.3%). Potential risk factors (presence of ticks on the animals, age, sex, use, habitat, and season) relating to the presence of Mediterranean spotted fever, or Boutonneuse fever, were evaluated. Animals used for guard or pastor activities and those living in rural areas (these factors are closely linked), together with those suffering from tick infestation, had significantly higher seroprevalence than the remainder. The frequency of seropositive dogs increased during the summer months, and these coincide with the period of greatest activity by the vector. Sex and age variables were not identified as risk factors.

Canine exposure to Borrelia burgdorferi and prevalence of Ixodes dammini (Acari: Ixodidae) on deer as a measure of Lyme disease risk in the northeastern United States.

Surveillance programs that identify areas where both the vector (Ixodes dammini) and etiologic agent (Borrelia burgdorferi) are present may identify the risk of Lyme disease and its spread earlier and more accurately than do programs relying on any single method, particularly human case reports. Hunter-killed deer (n = 1,204) from 22 counties in Maryland, Massachusetts, New Hampshire, New York, and Pennsylvania were examined in fall 1989 and all ectoparasites were identified. The following spring, canine sera (n = 884) were obtained from these sites, which included known endemic areas and those where Lyme disease is uncommon, and tested by enzyme-linked immunosorbent assay. Regression analysis of canine seroprevalence versus tick prevalence on deer from the same counties demonstrate a significant positive linear relationship. Sites were designated as low-, moderate-, or high-risk counties based upon their position on the regression curve. The geographic distribution of the sites correlated well with the distribution of known Lyme disease endemic and nonendemic areas. Locations were also identified where Lyme disease may be emerging. The positive relationship between measures of vector and pathogen abundance determined in this study permits public health workers to identify endemic and potentially endemic areas independently of human case reports.

Dogs as sentinels for Lyme disease in Massachusetts.

An investigation of the relationship between incident human cases of Lyme disease and seroprevalence of antibodies to B. burgdorferi in dogs was undertaken in order to determine whether dogs might serve as sentinels for Lyme disease. 3011 canine serum samples were analyzed by ELISA for antibody to B. burgdorferi. Records of incident human cases of Lyme disease were obtained from the Massachusetts Department of Public Health. Regression analyses of the relationship between the log10 (mean incidence in people 1985-1989) and canine seroprevalence from July 1988-August 1989 revealed that canine seroprevalence was highly predictive of incidence (R2 = 0.86, p less than .0001). A logistic regression model that incorporates the altitude of the town where each dog was resident, the date of sampling, and information on each dog's age, sex, and breed adequately explained the risk of canine seropositivity. Dogs resident at altitudes less than 200 feet, of sporting or large mixed breeds, and greater than two years of age were five times, four times, and almost three times more likely, respectively, to exhibit seropositivity than were other dogs. Estimates of the prevalence of antibody to B. burgdorferi in dog populations offers a sensitive, reliable, and convenient measure of the potential risk to people of B. burgdorferi in the environment. Risk factors for canine seropositivity may directly or indirectly illuminate certain aspects of the epidemiology of human Lyme disease.

Canine seroprevalence and the distribution of Ixodes dammini in an area of emerging Lyme disease.

This study evaluates the relative usefulness of canine serosurveys to predict risk of exposure in an area of emerging Lyme disease by comparing the distribution of canine seroprevalence with that of vector ticks. From 16 veterinary clinics throughout the State of Maine, 828 canine sera were obtained during the heartworm-testing months of April and May 1989 and measured for anti-Borrelia antibodies by enzyme-linked immunosorbent assay. In the same year, 1605 ticks, including 585 Ixodes dammini, were collected from pets, humans, small mammals, and deer. Thirty-six dogs were seropositive, 28 of which had not traveled to endemic areas. Eighty-nine percent of all seropositive dogs were from towns within 20 miles (32 km) of the coast; the great majority lived within 5 miles (8 km) of tidewater (odds ratio =4.45, P = .002). Positivity varied from 17% in a southern coastal clinic to 0% in four northern clinics. Of 585 I. dammini identified, all but 5 (99.1%) were also from towns within 20 miles of the coast. Comparison of I. dammini submissions with those of another commonly found tick, Ixodes cookei, corroborated this predominantly coastal distribution. Canine seropositivity generally coincided with this coastal range. These data predicted areas of risk for human Lyme disease, although the prevalence of reported cases remained low.

Serosurvey of shelter dogs in Virginia for antibodies to Borrelia burgdorferi

Increased interest and concern about Lyme disease in the last several years, along with the close proximity of Maryland's endemic foci, has raised questions about the incidence of Lyme disease in Virginia. A canine seroprevalence survey was undertaken in an attempt to estimate the prevalence of borreliosis in Virginia. An ELISA test was used to detect antibodies against Borrelia burgdorferi in sera from 221 shelter dogs from the three different physiographic regions in Virginia. From those animals sampled, only one dog was seropositive. This finding was consistent with other studies which have found limited evidence of Lyme disease in Virginia.