Seroprevalence of canine influenza virus (H3N8) in Iditarod racing sled dogs

We conducted a cross-sectional convenience sampling study of dogs racing in the 2010 Iditarod to determine the seroprevalence of canine influenza virus (CIV) in the sled dog population. Questionnaires were completed detailing medical and CIV vaccination history, kennel size and location, travel history, and social interactions for each team. A total of 399 dogs were tested for CIV antibodies by hemagglutination inhibition assay. None of these, including 39 samples from dogs reported as CIV vaccinated, were seropositive for CIV antibodies. All of the vaccinated dogs were also negative on virus microneutralization assay. Risk factors for CIV seropositivity could not be determined due to a lack of positive samples. This is the first published study investigating the prevalence of CIV in sled dogs and additional studies are warranted to assess CIV infection among racing sled dogs and to evaluate the ecology of CIV and the vaccine efficacy in this population of dogs.     

The Seroprevalence of Canine Influenza Virus H3N8 in Dogs Participating in a Flyball Tournament in Pennsylvania in 2010: A Follow‐Up Study

Background

Canine influenza virus (CIV) H3N8 infection is thought to be highly contagious and potentially deadly. Low seroprevalence in dogs participating in the sport of flyball in 2009 was reported. It remains unknown if prevalence is changing in dogs at risk.

Objective

To determine seroprevalence of antibodies to CIV H3N8 in a population of pet dogs that participated in an indoor flyball tournament in Pennsylvania in November 2010.

Animals

Dogs participating in a flyball tournament.

Methods

Medical, travel, and activity histories for previous 10.5 months were obtained from consenting owners and serum samples were collected from dogs. Antibodies to CIV H3N8 were measured using hemagglutination inhibition.

Results

Of 251 competing dogs, 103 dogs were tested. Overall, seroprevalence of CIV H3N8 in dogs participating in flyball was 1.9% (95% CI, 0.05–6.8%). Thirty‐five dogs were tested in both 2009 (all titers <8) and 2010 (all titers <8). Ten of 103 dogs had been vaccinated for CIV H3N8. Two dogs had positive titers (>8) and both had been vaccinated twice in the previous month. Titers in remaining 8 vaccinated dogs were undetectable. Seroprevalence in vaccinated dogs was 20% (95% CI, 5.7–50.1%), whereas in unvaccinated dogs it was 0% (95% CI, 0–4.0%). Although 7 dogs had history of respiratory signs, only 1, which was vaccinated, was serologically positive for CIV H3N8.

Conclusions

Consistent with low prevalence of CIV H3N8 exposure previously reported in flyball dogs, unvaccinated dogs had 0% prevalence, suggesting a stable exposure rate. However, low seroprevalence may result in unprotected flyball dogs at risk for developing CIV H3N8.     

Serological evidence of H3N8 canine influenza-like virus circulation in USA dogs prior to 2004

H3N8 canine influenza virus (H3N8 CIV) was first reported as a novel canine respiratory pathogen in racing greyhounds and shelter dogs in the U.S.A. in 2004. Phylogenetic analyses determined that this host-adapted pathogen originated from interspecies transmission of an equine influenza virus (EIV), but it is unknown when the transmission occurred prior to discovery in 2004. The objective of this study was to determine if racing greyhound and shelter dog sera collected from 1984 to 2004 had serological evidence of exposure to H3N8 CIV or EIV. Archived sera from 702 racing greyhounds and 1568 shelter dogs were tested for H3 antibodies to the original 2004 CIV isolate, as well as EIV isolates from 1991 to 1999. None of the racing greyhounds from 1984 and 1985 had detectable H3 antibodies. One of the shelter dogs, which entered a north Florida shelter in 2004, was seropositive. For racing greyhounds sampled from 1999 to 2004, 133/520 (26%) dogs had antibodies to both CIV and EIV H3 proteins. The annual seroprevalence was 27% in 1999, 28% in 2000, 10% in 2001, 1% in 2002, 41% in 2003, and 28% in 2004. The odds of H3 seropositivity were greater among dogs that raced > or =6 months, raced on > or =2 tracks, and raced in 1998, 2002, and 2003. Many of the seropositive dogs raced at tracks that were involved in 'kennel cough' epidemics in 1998-1999 and 2002-2003. Based on serological evidence, a H3N8 canine influenza-like virus was circulating in racing greyhounds in the U.S.A. as early as 1999.     

Risk factors for canine neosporosis in farm and kennel dogs in southern Italy

Neosporosis by Neospora caninum causes losses to livestock production through abortion in cattle while, in dogs, it induces neuromuscolar disease. This study investigated neosporosis seroprevalence associated risk factors (including the seropositivity to leishmaniosis) in dogs of southern Italy, determined the prevalence of N. caninum oocyst shedding and examined the relationship between seroprevalence of neosporosis in farm dogs and cattle. Using an inhibition ELISA, 20.9% of 306 dogs had percent inhibition values >10 (indicative of exposure) and farm dogs had a significantly (p<0.001) higher seroprevalence than dogs in a rescue kennel. Whilst N. caninum seroprevalence was associated with increasing age in dogs (p< or =0.01) there was no association between seropositivity for N. caninum and for Leishmania infantum. Oocysts of N. caninum were not detected in faecal samples from 230 dogs including 160 farm dogs. The results indicated that neosporosis infection is common in southern Italy both in dogs and in cattle and that dogs at higher risk of exposure are free-ranging ones living in farms. The lack of correlation between canine seroprevalence for N. caninum and L. infantum assumes a particular significance in an endemic area for leishmaniosis.     

Prevalence of antibodies to Neospora caninum in dogs of rural or urban origin in central New Zealand

AIM: To investigate the seroprevalence of Neospora caninum infection in populations of dogs from dairy farms, sheep/beef farms and urban areas in the central part of New Zealand. It was postulated seroprevalence would be higher for farm dogs than urban dogs if the life-cycle of this parasite involves transmission between dogs and cattle.

METHODS: Serum samples were obtained from dogs that lived on dairy farms (n=161), sheep/beef farms (n=154) and in urban situations (n=150). The relative risk of detecting antibodies to N. caninum using an immunofluorescent antibody test (IFAT) was compared between farm and urban dogs.

RESULTS: The relative risk of having a titre of ≥1:200 to N. caninum was 2.43 (95% CI=1.88-3.14) for dairy-farm dogs and 3.16 (95% CI=2.48–4.02) for sheep/beef-farm dogs, compared with urban dogs. At this titre, which is currently used in New Zealand to indicate seropositivity, seroprevalence of N. caninum infection was 30.7% in urban dogs, 74.5% in dairy-farm dogs and 96.8% in sheep/beef-farm dogs.

CONCLUSION: This observation is consistent with a cycling of this disease between cattle and dogs on farms in New Zealand and with higher exposure of dogs to N. caninum on farms than occurs in urban environments. The prevalence of antibodies in all three groups of dogs tested in this study (dairy-farm dogs, sheep/beef-farm dogs and urban dogs) is higher than has generally been reported elsewhere. New Zealand farm dogs have a higher serological prevalence of N. caninum infection than urban dogs.

CLINICAL RELEVANCE: Management and disease control practices that break the life-cycle of transmission between cattle and dogs should assist in controlling cattle abortion due to N. caninum.     

The seroprevalence of canine respiratory coronavirus and canine influenza virus in dogs in New Zealand

Abstract

AIM: To determine whether canine respiratory coronavirus (CRCoV) and canine influenza virus (CIV) are present in dogs in New Zealand.

METHODS: Serum samples from 251 dogs of varying age, breed and clinical histories were tested for the presence of antibodies to CRCoV and CIV, using indirect fluorescent antibody (IFA) analysis. The population sampled represented a wide geographic area but principally encompassed the central and lower North Island of New Zealand.

RESULTS: Seventy-three of the 251 samples (29%) were seropositive for CRCoV. Dogs <2 years old were less likely to be seropositive for CRCoV than older dogs. None was seropositive for CIV.

CONCLUSIONS: This study revealed the presence of antibodies to CRCoV in dogs in New Zealand. Young dogs are less likely to be seropositive than older dogs, probably due to increased opportunity for exposure to CRCoV over time. Serum antibodies to CIV were not detected in any of the dogs sampled, suggesting that this virus is unlikely to be present in dogs in New Zealand.

CLINICAL RELEVENCE: Canine respiratory coronavirus is present in New Zealand. Although the role of this virus in canine infectious tracheobronchitis has not been fully elucidated, evidence suggests that it may have a causal role in this disease. Veterinarians should consider CRCoV as a differential diagnosis in cases of respiratory disease in dogs in New Zealand. While CIV appears not to be currently present in New Zealand, veterinarians should consider infection with this virus as a differential diagnosis in dogs presenting with respiratory signs.     

Seroprevalence of spotted fever group rickettsiae in canines along the United States–Mexico border

Portions of northern Mexico are experiencing a re‐emergence of Rocky Mountain spotted fever (RMSF), a tickborne disease caused by Rickettsia rickettsii, a member of the spotted fever group of rickettsiae (SFGR). Infection with R. rickettsii can result in serious and life‐threatening illness in people and dogs. Canine seroprevalence has been used as a sentinel for human RMSF in previous studies. This study aims to quantify SFGR seroprevalence in canines in three northern Mexican states and identify risk factors associated with seropositivity. A total of 1,136 serum samples and 942 ticks were obtained from dogs participating in government sterilization campaigns and from animal control facilities in 14 Mexican cities in three states. SFGR antibodies were detected using indirect immunofluorescence antibody assays at titre values ≥1/64. Six per cent (69 dogs) showed antibodies to SFGR, with the highest seroprevalence reported in Baja California (12%), Coahuila (4%) and Sonora (4%). Dogs from Baja California had three times higher odds of having SFGR antibodies compared to dogs from Sonora (OR = 3.38, 95% CI, 1.81–6.37). Roughly one quarter (25%) of surveyed dogs were parasitized by ticks (Rhipicephalus sanguineus sensu lato) at the time of sample collection. A portion of collected ticks were tested for rickettsial DNA using polymerase chain reaction. Positive samples were then sequenced, showing evidence of SFGR including R. massiliae, R. parkeri and R. rickettsii. Dogs that spent the majority of time on the street, such as free‐roaming or community‐owned dogs, showed a greater risk of tick infestation, seropositivity, bearing seropositive ticks, and may play a pivotal role in the spread of SFGR among communities. Estimating the seroprevalence of SFGR in the canine population can help public health campaigns target high‐risk communities for interventions to reduce human RMSF cases.     

Spatial distribution of seroprevalence for Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia canis, and Dirofilaria immitis in dogs in Washington, Oregon, and California

Background: In the US little spatially defined information regarding exposure to most vector‐borne pathogens in dogs is available for the states of California (CA), Oregon (OR), and Washington (WA). Objectives: The purpose of the present study was to evaluate the spatial distribution of seroprevalence for 4 vector‐borne pathogens, Anaplasma phagocytophilum, Borrelia burgdorferi, Ehrlichia canis, and Dirofilaria immitis, across the 3 western coastal states of the contiguous United States that extend from the northern Mexican to the southern Canadian border. Methods: A convenience sample, targeting blood from 20 pet dogs per county across CA, OR, and WA, was evaluated using a canine point‐of‐care ELISA kit. Geographic coordinates of home zip code were displayed using a geographic information system. A total of 2431 dogs from CA, OR, and WA were tested. Results: The overall seroprevalence was highest for A. phagocytophilum (2.4%), followed by B. burgdorferi (1.2%), and E. canis (0.7%). The prevalence of infection with D. immitis was 0.7%. At the individual dog level, there was a significant association between seropositivity to B. burgdorferi and A. phagocytophilum (odds ratio=18.7, 95% confidence interval=6.8–47.1). For most positive results, prevalence tended to decrease with increasing latitude; thus, the highest rates of seropositivity occurred in CA, followed by OR, and then WA; one exception was seropositivity for B. burgdorferi, which was higher in WA (0.38%) than in OR (0.15%), but considerably lower than in CA (2.00%). In WA, dogs that tested positive for A. phagocytophilum, E. canis, and B. burgdorferi were in the southern Puget Sound area. For D. immitis, none of the dogs in WA was positive. Conclusions: Seropositivity for vector‐borne pathogens is broadly but patchily distributed in dogs in CA, OR, and WA.     

Seroepidemiology of Toxoplasma gondii and Neospora caninum in dogs from the state of Paraíba, Northeast region of Brazil

A cross-sectional study was conducted to determine the seroprevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies and to investigate the risk factors related to antibodies against T. gondii and N. caninum in dogs of the city of Campina Grande, state of Paraiba, Northeast region of Brazil. For this purpose, 286 blood samples were collected from dogs during the rabies vaccination campaign, in September 2003, and on this occasion questionnaires addressing epidemiological aspects of the infections were given to each dog owner. The sera were analyzed for anti-T. gondii and anti-N. caninum antibodies by indirect fluorescent antibody tests. Of the total of 286 dogs, 129 were positive for T. gondii (titer16) with a prevalence value of 45.1% (95% CI=39.24-51.07%). For N. caninum, 24 dogs were positive (titer50), with a prevalence value of 8.4% (95% CI=5.45-12.23%). Antibodies to T. gondii and N. caninum were found simultaneously in 14 dogs (4.9%; 95% CI=2.7-8.08%). For T. gondii infection, the risk factors associated with seroprevalence was the age of the animals, with dogs older than one year presenting higher values of odds ratio, and co-habitation of cats in the household. For N. caninum infection, dogs that have street contact had higher odds of seropositivity than dogs that remained exclusively in a domestic environment.     

Serosurvey of Babesia canis, Babesia gibsoni and Ehrlichia canis in pound dogs in California, USA

The seroprevalence of three canine tick-transmitted parasites, Babesia gibsoni, Babesia canis and Ehrlichia canis, was estimated in selected regions of California. Blood smears and sera were obtained from 971 dogs in seven animal shelters: four in Los Angeles County, one in Yolo County, one in El Dorado County in California and one in Minden, Nevada. Seroprevalence in Los Angeles County shelters were 0–13%, 0–2.6% and 0% for B. canis, B. gibsoni and E. canis, respectively. Seroprevalences of the same three parasites in Yolo County and El Dorado County Shelters were 0% except for a 1% seroprevalence of B. canis in dogs from Yolo County Shelter.

Potential risk factors (breed, age, sex and evidence of ticks on the dogs) for B. canis seropositivity were evaluated. Dogs 3 years of age or older had a significantly higher risk (odds ratio 5.04) of being seropositive to B. canis compared with dogs less than 1 year old. Breed, sex and evidence of ticks were not associated with seropositive reactions to B. canis. Of 29 coyotes captured in Los Angeles County, three (10.3%) were seropositive for B. gibsoni, with titers of 1280 to 2560. This study indicated that dogs in Los Angeles County were at higher risk of being seropositive and potentially infected with canine babesial parasites than dogs in Yolo and El Dorado Counties. Movement of chronically infected dogs from Los Angeles County into other areas could contribute to the spread of these important pathogens.     

Serological survey of Neospora caninum and Leishmania infantum co-infection in dogs

A seroprevalence survey and risk analysis of Neospora caninum and Leishmania infantum was conducted in dogs from an area of the Campania region of southern Italy, in order to investigate the co-infection of these two protozoa.Blood samples were collected from 1058 asymptomatic dogs over a 18 months period. Serum samples were tested for antibodies to N. caninum and to L. infantum using the indirect fluorescent antibody test.Epidemiological data (breed, age, sex, and utilization) were collected and statistically analysed in relation to N. caninum and to L. infantum seropositivity and antibody titres.Out of the 1058 sera samples tested, 68 (6.4%) were found to have antibodies to N. caninum, and 222 (21.0%) to have antibodies to L. infantum. The co-presence of antibodies to N. caninum and to L. infantum was found in 46 (4.3%) dogs. Thus, 67.6% of the dogs positive for N. caninum also had antibodies to L. infantum.The major risk factor for N. caninum seropositivity was the presence of antibodies to L. infantum, and the major risk factor for L. infantum seropositivity was the presence of antibodies to N. caninum. In addition, high N. caninum seroprevalence was closely correlated to Boxer breed, and high L. infantum seroprevalence was correlated to masculine gender and Setter and Pit bull breeds. Low L. infantum seroprevalence was closely correlated to Yorkshire breed.The findings of this survey indicate that in the Campania region of southern Italy the co-presence of antibodies to N. caninum and to L. infantum is very common in dogs, and that infection by one protozoan seems to enhance the susceptibility to the other one. This is probably due to the immunological status of the tested dogs.     

Seroprevalence and risk factors associated with Neospora caninum infection in different dog populations in Spain

In this study, Neospora caninum seroprevalence and some associated risk factors were investigated in four different dog populations in Spain. N. caninum seropositivity was significantly higher in farm dogs (51%, 51/100) (P<0.001) and lower in household dogs (2.9%, 3/102) (P<0.0001). The seroprevalence in hunting (23%, 23/100) and stray (24.5%, 23/94) dogs was moderate, and no significant differences were observed between these two populations (P>0.05). A significantly higher number of dogs showed titres of 1:50-1:100 (68%, 68/100) than >or=1:200 (33%, 33/100) titres (P<0.0001). N. caninum antibodies were more often detected in mixed breed than pure breed dogs (P<0.01), but when data were stratified by dog type a significant association was not found (P>0.05). A significantly higher prevalence of N. caninum was observed in dogs over 1 year old (P<0.01), indicating that horizontal transmission may be the most important route of infection. The presence of N. caninum antibodies was significantly more frequent in Leishmania infantum-seropositive hunting (P<0.05) and stray dogs (P<0.00001). This study confirms that farm, stray and hunting dogs can be considered at-risk dog populations for N. caninum infection in Spain.     

Seroprevalence of Coxiella burnetii in Australian dogs

The role of dogs in the transmission of Coxiella burnetii to humans is uncertain, and extensive seroprevalence studies of dogs have not been previously conducted in Australia. This study determined C. burnetii exposure in four diverse canine subpopulations by adapting, verifying and comparing an indirect immunofluoresence assay (IFA) and an enzyme‐linked immunosorbent assay (ELISA) used to detect anti‐C. burnetii antibodies in humans. Canine serum samples (n = 1223) were tested with IFA from four subpopulations [breeding establishments; household pets; free‐roaming dogs in Aboriginal communities; shelter dogs]. The proportions of seropositive dogs were as follows: breeding (7/309, 2.3%), household pets (10/328, 3%), Aboriginal communities (21/321, 6.5%) and shelters (5/265, 1.9%). Dogs from Aboriginal communities were 2.8 times (CI 1.5–5.1; P < 0.001) more likely to be seropositive than dogs from other populations. The ELISA was used on 86 of 1223 sera tested with IFA, and a Cohen's Kappa coefficient of 0.60 (CI 0.43–0.78) indicated good agreement between the two assays. This study has established that Australian dogs within all four subpopulations have been exposed to C. burnetii and that a higher seroprevalence was observed amongst free‐roaming dogs associated with Aboriginal communities. As C. burnetii recrudesces during pregnancy and birth products contain the highest concentration of organism, individuals assisting at the time of parturition, those handling pups shortly after birth as well as those residing in the vicinity of whelping dogs are potentially at risk of developing Q fever. However, the identification of active antigen shed in excreta from seropositive dogs is required in order to accurately define and quantify the public health risk.     

Serological survey of Neospora caninum in dogs in the Czech Republic and a long-term study of dynamics of antibodies

The main aim of the present study was to establish the prevalence of antibodies against Neospora caninum dogs from the Czech Republic and to examine the dynamics of antibody titers during a long-term period. For this purpose, sera of 858 dogs were examined for the presence of anti-N. caninum antibodies using an indirect immunofluorescent antibody test (IFAT). Four groups of dogs of various origins were included in the survey: the first group (A, n=470) comprised dogs purchased by the Czech Army from the civilian sector throughout the Czech Republic, with 22 (4.7%) N. caninum-positive dogs, second group (B, n=115) represented police dogs with no seropositive animal, third group (C, n=195) were pet dog sera collected for veterinary clinic with 5 (2.6%) anti-N. caninum sera and the fourth group (D, n=78) of canine shelter dogs with the seroprevalence of 19.2%. The differences in seroprevalence were significant (P< or =0.01) between groups B and A, and between D and A. None of the serologically positive animals had clinical signs of neurological disorders. Coprological examination did not reveal any dog shedding N. caninum oocysts. The seropositivity rates for N. caninum were analyzed in relation to other data, such as age, breed and gender. Increased prevalence rates of anti-N. caninum antibodies were found in the older age strata of the dog population sample tested in the present study. We found significantly higher (P=0.02) prevalence in 3-3.5-year-old dogs (11.1% of 36), as compared to 1-1.5-years-old dogs (2% of 98). A longitudinal study of antibody dynamics was carried out in 19 initially seropositive dogs over a period of 4 years. The second and third examinations revealed that antibody titers decreased in majority of positive dogs (10, 52.6%), of which in seven cases (36.8%) the titers fell to levels that are currently considered as being seronegative (titer <1:50), or even became undetectable (titer <1:25).     

A serological survey of canine H3N2, pandemic H1N1/09 and human seasonal H3N2 influenza viruses in dogs in China

Influenza viruses have been isolated from dogs in China; however, the extent of influenza infection among dogs is not yet clear. Here, we examined the seroprevalence of avian-origin canine H3N2, pandemic H1N1/09 and human seasonal H3N2 influenza viruses in pet dogs in China during January 2012 to June 2013. The seropositivity rate of canine H3N2, H1N1/09 and human H3N2 were 3.5%, 1.5%, and 1.2%, respectively. Dogs aged 2–5 years were most commonly seropositive to canine H3N2 virus. It is worth noting that two serum samples were positive against both canine H3N2 and H1N1/09 viruses, suggesting the possibility of coinfection with both viruses. Our findings emphasize the necessity for continued surveillance of influenza viruses in dogs in China.     

No evidence of horizontal infection in horses kept in close contact with dogs experimentally infected with canine influenza A virus (H3N8)

Background

Since equine influenza A virus (H3N8) was transmitted to dogs in the United States in 2004, the causative virus, which is called canine influenza A virus (CIV), has become widespread in dogs. To date, it has remained unclear whether or not CIV-infected dogs could transmit CIV to horses. To address this, we tested whether or not close contact between horses and dogs experimentally infected with CIV would result in its interspecies transmission.

Methods

Three pairs of animals consisting of a dog inoculated with CIV (10^8.3 egg infectious dose₅₀/dog) and a healthy horse were kept together in individual stalls for 15 consecutive days. During the study, all the dogs and horses were clinically observed. Virus titres in nasal swab extracts and serological responses were also evaluated. In addition, all the animals were subjected to a gross pathological examination after euthanasia.

Results

All three dogs inoculated with CIV exhibited clinical signs including, pyrexia, cough, nasal discharge, virus shedding and seroconversion. Gross pathology revealed lung consolidations in all the dogs, and Streptococcus equi subsp. zooepidemicus was isolated from the lesions. Meanwhile, none of the paired horses showed any clinical signs, virus shedding or seroconversion. Moreover, gross pathology revealed no lesions in the respiratory tracts including the lungs of the horses.

Conclusions

These findings may indicate that a single dog infected with CIV is not sufficient to constitute a source of CIV infection in horses.     

Prevalence of antibodies to Neospora caninum in dogs of rural or urban origin in central New Zealand

AIM: To investigate the seroprevalence of Neospora caninum infection in populations of dogs from dairy farms, sheep/beef farms and urban areas in the central part of New Zealand. It was postulated seroprevalence would be higher for farm dogs than urban dogs if the life-cycle of this parasite involves transmission between dogs and cattle. METHODS: Serum samples were obtained from dogs that lived on dairy farms (n=161), sheep/beef farms (n=154) and in urban situations (n=150). The relative risk of detecting antibodies to N. caninum using an immunofluorescent antibody test (IFAT) was compared between farm and urban dogs. RESULTS: The relative risk of having a titre of > or = 1:200 to N. caninum was 2.43 (95% CI=1.88-3.14) for dairy-farm dogs and 3.16 (95% CI=2.48-4.02) for sheep/beef-farm dogs, compared with urban dogs. At this titre, which is currently used in New Zealand to indicate seropositivity, seroprevalence of N. caninum infection was 30.7% in urban dogs, 74.5% in dairy-farm dogs and 96.8% in sheep/beef-farm dogs. CONCLUSION: This observation is consistent with a cycling of this disease between cattle and dogs on farms in New Zealand and with higher exposure of dogs to N. caninum on farms than occurs in urban environments. The prevalence of antibodies in all three groups of dogs tested in this study (dairy-farm dogs, sheep/beef-farm dogs and urban dogs) is higher than has generally been reported elsewhere. New Zealand farm dogs have a higher serological prevalence of N. caninum infection than urban dogs. CLINICAL RELEVANCE: Management and disease control practices that break the life-cycle of transmission between cattle and dogs should assist in controlling cattle abortion due to N. caninum.     

Canine neosporosis in Hungary: screening for seroconversion of household, herding and stray dogs

In order to assess the seroprevalence of canine neosporosis 651 blood samples were collected from 586 household, 41 herding and 24 stray dogs, at small animal clinics in four large cities and other places of Hungary. Nineteen (2.9%) showed positivity in the IFAT with titres between 1:80 and 1:10240. Two dogs with high titres of antibodies to Neospora caninum had neuromuscular signs (imbalance, tremor) and a further one developed papulomatous, ulcerative and necrotizing dermatitis. There was no correlation between titers and age, sex, breed or keeping place. Although more male dogs had antibodies to N. caninum than females in case of both household and herding dogs, this association was not significant. No breed predisposition was observed. However, dogs with seroconversion were significantly more prevalent among rural (6%) than among urban dogs (1%), indicating that dogs in the countryside may have contact with or access to potentially infected offal from cattle and other intermediate hosts more frequently than those in large cities. Furthermore, significantly more herding dogs (29.3%) had antibodies to N. caninum than household dogs (1.2%), confirming the association between the occurrence of neosporosis and dog keeping on farms. The 12 dogs found seropositive among herding ones lived on 6 farms, on 5 of which seropositive cattle were also identified. This is the first report on the prevalence of N. caninum infection in dogs in Hungary.     

Cross-sectional serological study of canine Leishmania infection in Fortaleza, Ceará state, Brazil

Visceral leishmaniasis (VL) is one of the most important reemerging parasitic disease in the world. The domestic dog is the main reservoir in urban environments. The aim of this work was to extend the knowledge on canine Leishmania infection in the city of Fortaleza in northeastern Brazil, identifying the risk factors inherent in dog susceptibility to the infection. Two populations were analyzed, domestic dogs from clinics and the Veterinary Hospital Unit of Ceará State University and stray dogs captured by the Center for Zoonosis Control in Fortaleza. Blood samples were collected and centrifuged and the sera were stored at -20 degrees C. ELISA, with soluble crude Leishmania chagasi antigens (LTCC - WDCM731) was used for diagnosis. A total of 1,381 samples were tested, 750 from domestic and 631 from stray dogs. The seroprevalence of canine VL was 21.4% (135/631) in stray dogs and 26.2% (197/750) in domestic dogs. The seroprevalence of Leishmania infection in the six administrative regions of the city (Secretarias Executivas Regionais, or SER) among stray dogs was highest in SER V, representing 31.4% of the cases, with large dogs more infected (27.7%). Among domestic dogs Leishmania infection was most prevalent in SER V (38.5%) and VI (37.6%). The dogs' age (1-6 years), large size, environment with dense vegetation and presence of clinical signs compatible with Leishmania infection were associated with the illness in domestic dogs. The frequency of the infection varied seasonally. The seroprevalence was greatest in July and December. These results confirm Fortaleza is an endemic area for canine VL and suggest some variables associated with increasing infection risk in dog populations.     

Risk factors for equine monocytic ehrlichiosis seropositivity in horses in Colorado

A study was conducted in April through August 1989 whereby 318 horses were tested for immunofluorescent antibody (IFA) titers to Ehrlichia risticii. The state of Colorado was divided into four regions and an approximately equal number of horses was tested in each region. Questionnaires were completed for each horse; a multiple logistic regression model was used to identify risk factors for horses being exposed to E. risticii.

Of the 318 horses tested, 48 (16%) had IFA titers of 1:40 or greater (range 1:40–1:1280). There was no association between the region of Colorado and seropositivity. Other variables which were not identified as risk factors included gender, transportation to other parts of Colorado, transportation to other states and exposure to other horses. When the variables were examined individually, older horses, Quarter horses, horses housed at a boarding stable, and horses having access to pasture or direct access to a stream, pond or lake were more likely to have positive titers. Horses confined to a stall with a run were less likely to be exposed to E. risticii. All apparent associations disappeared when the factors were tested in the multiple logistic regression model.