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.     

Canine infection and the possible role of dogs in the transmission of American tegumentary leishmaniosis in Salta,Argentina

Some Leishmania species affect humans in two principal forms: visceral and cutaneous leishmaniosis (CL). Several studies have identified dogs as the main reservoirs of the visceral leishmaniosis (VL) caused by Leishmania infantum. The purpose of this work was to carry out a survey of the canine population associated with human cases of American tegumentary leishmaniosis (ATL), in order to establish the clinical, parasitological, serological and immunological characteristics of the canine disease, in an endemic region for both ATL and Chagas' disease in the province of Salta, in northwestern Argentina. Two hundred and eight dogs from the endemic area were examined and 41 (19.7%) of them presented lesions compatible with leishmaniosis. In order to investigate the presence of antibodies against Leishmania spp. and Trypanosoma cruzi, sera were screened by ELISA using two complex antigens from these parasites and, because of cross-reactions between them, a specific antigen for diagnosis of T. cruzi infection. Sixty-two (29.8%) of 208 dogs were positive for the complex antigen F45 from Leishmania and 50 (24%) were positive for the complex antigen F105 from T. cruzi. Nine dogs (4.3%) were positive for the specific Ag163B6-cruzipain suggesting that these dogs were truly infected with T. cruzi. Furthermore, three of these nine dogs presented Leishmania sp. in their skin lesions and therefore were considered as infected by both, T. cruzi and Leishmania parasites. The prevalence of Leishmania infection detected by lesions and/or positive serology was 27.4% (57/208). On the basis of previous observations regarding the clustered appearance of human ATL, the dog population was divided into two groups: zone A, dogs living within a 100 m radius from houses with human cases, and zone B, dogs living beyond this limit. The prevalence of ATL in dogs was significantly higher in zone A (34.6%) than in zone B (7.3%), suggesting a strong correlation between canine and human cases. The average time required for a parasitological diagnosis by microscopy was six times longer for dog samples than human ones, and the average number of parasites per 100 microscopic fields was 14-fold lower in canine samples. The high prevalence of Leishmania infection and the close association with human cases, demonstrated that dogs are a very susceptible host for Leishmania infection, but the scarcity of parasites in their lesions suggests that they may not be the main reservoir of the parasite in this endemic area.     

Epidemiological aspects of canine visceral leishmaniosis in the Islamic Republic of Iran

An epidemiological study to examine the sero-prevalence of zoonotic visceral leishmaniosis (ZVL) among domestic and wild canines in endemic foci of Iran was carried out during 1999-2003 to assess the distribution of the disease and the possible association between infection in dogs, wild canines and people. Anti-leishmanial antibodies were detected by the direct agglutination test (DAT). Parasitological study was performed for all captured wild canines and were detected in some of the seropositive dogs with specific clinical signs (n=107). Serum samples (n=1568) were collected from domestic dogs in villages that are known endemic foci of human visceral leishmaniosis (HVL). Wild canine sera were collected from jackals (Canis aureus, n=10), foxes (Vulpes vulpes, n=10) and wolves (Canis lupus, n=10). Of the 1568 serum sampled collected from domestic dogs, 222 (14.2%) were positive by DAT (1:320 and above). No statistically significant difference was found between male (15.2%) and female (11.8%) sero-prevalence (P=0.083). Dogs of 8 years and above showed the highest sero-prevalence (40.6%). Only 23.9% of the seropositive domestic dogs had clinical signs. Parasitology and serology tests that were performed in 30 wild canines showed 10% these animals were infected by Leishmania infantum. Ten out of 11 Leishmania spp. isolated from the dogs and wild canines were identified as L. infantum and one other as L. tropica by molecular and biochemical techniques. For the first time in Iran, L. infantum and L. tropica were isolated from viscera of both a wolf and a domestic dog.     

Seroepidemiological survey on canine leishmaniasis among dogs from an urban area of Brazil

A cross-sectional seroepidemiological survey on canine leishmaniasis among pet dogs was carried out in an urban area in the State of Pernambuco (Brazil) where human cases of visceral leishmaniasis have sporadically been reported. Using an indirect fluorescent antibody test, anti-Leishmania antibodies were detected in 130 out of 322 dogs, confirming previous exposure to Leishmania parasites. The overall seroprevalence found was 40.3% (95% confidence interval: 34.9-45.9). Data analysis revealed that serological positivity was statistically associated with male (chi2=20.60, P-value=0.000) and juvenile dogs (chi2=4.24, P-value=0.039). Furthermore, it was observed that 85.3% of all seropositive dogs showed no clinical signs of leishmaniasis. The results showed a high seroprevalence of anti-Leishmania antibodies among dogs from an urban area of Pernambuco - with a large proportion of asymptomatic seropositive dogs - indicating that the prevalence of Leishmania infection in this area has been underestimated.     

Evaluation of the presence of Leishmania spp. by real-time PCR in the lacrimal glands of dogs with leishmaniosis

Leishmania infantum infection is highly prevalent in endemic areas. Dogs with leishmaniosis may develop keratoconjunctivitis sicca (KCS). The goals of this study were (1) to quantify Leishmania amastigotes in the Meibomian glands (MG), main lacrimal gland (MLG) and nictitating membrane gland (NMG) from dogs with leishmaniosis; (2) to compare these results to immunohistochemistry (IHC), and (3) to explore the association between the Leishmania parasite load and the presence of ocular clinical signs. Twenty-five dogs diagnosed with leishmaniosis were included. MG, MLG and NMG from both eyes were collected. Histopathology, IHC and real-time PCR were performed. All specimens yielded positive real-time PCR results. For all three glands, samples from dogs with ocular clinical signs had mean ΔCt (cycle threshold) values significantly lower (higher parasite loads) than those from dogs without signs. Cut-off values of ΔCt<0, ΔCt<4 and ΔCt<4.9 for MG, MLG and NMG, resulted in a likelihood ratio of positives of 5.9, 6.38 and 6.38, respectively. Samples with ΔCt values below the reported cut-off were significantly more likely to display clinical signs related to KCS than those with results above the cut-off, for all three glands. Similarly, ΔCt values below the cut-off were significantly associated with positive IHC. In this study real-time PCR has been standardised for use in MG, MLG and NMG. A cut-off value established for each of these tissues may aid the clinician in the discrimination between ocular signs related to Leishmania from those associated with other causes of KCS.     

Can spleen aspirations be safely used for the parasitological diagnosis of canine visceral leishmaniosis? A study on assymptomatic and polysymptomatic animals

The purpose of this study was to evaluate the safety of spleen aspiration as a sampling technique for the parasitological detection by culture and microscopy of Leishmania (chagasi) infantum. Two hundred and nine domiciled dogs from an endemic area for visceral leishmaniasis in Bahia State, Brazil, were studied. Most dogs (87%) were seropositive for anti-L. chagasi antibodies by ELISA. Clinical signs of disease were recorded and the animals monitored during and after spleen puncture in order to detect possible complications associated with the procedure. From a total of 257 splenic punctures in the 209 animals, only three minor events occurred, with no significant consequence for the animals and no association with risk factors. Leishmania was isolated from 149/180 (83%) seropositive dogs, and from 6/26 (23%) seronegative animals. The procedure did not cause adverse side effects or unnecessary suffering and confirmed the diagnosis in a large percentage of dogs. We conclude that spleen aspiration can be considered an effective and safe procedure for the definitive diagnosis of canine visceral leishmaniosis.     

Detection of Leishmania infantum DNA by fret-based real-time PCR in urine from dogs with natural clinical leishmaniosis

The aim of this study was to detect Leishmania infantum DNA by real-time PCR in urine from different groups of dogs with clinical leishmaniosis. Urine from 10 clinically healthy dogs and 43 dogs with clinical leishmaniosis diagnosed by positive serology and/or bone marrow PCR were studied. The group of 43 dogs with clinical leishmaniosis was divided into three subgroups: 13 dogs with renal insufficiency and proteinuria (urine protein-creatinine ratio greater than one), 13 dogs with only proteinuria, and 17 dogs with neither renal insufficiency nor proteinuria. The detection of Leishmania DNA was performed by light cycler real-time PCR using hybridization probes in each urine sample. Leishmania positive PCR was found in 47% (20/43) of the urine from leishmaniotic dogs, while all urine from clinically healthy dogs were negative. The percentages of positive Leishmania PCR were 85% (11/13) in dogs with renal insufficiency and proteinuria, 23% (3/13) in dogs with proteinuria and 35% (6/17) in dogs with neither renal insufficiency nor proteinuria. Dogs with renal insufficiency and proteinuria presented a statistical significant greater percentage of positive Leishmania PCR in urine when compared with the other subgroups (P<0.02). This study demonstrates the presence of Leishmania DNA in urine of dogs with leishmaniosis. Those dogs with severe renal damage present a greater number of Leishmania parasites in urine.     

Detection of Leishmania amastigotes in peripheral blood from four dogs--Short communication

The authors carried out microscopic examination of blood smears of 1438 dogs infected with Leishmania infantum. Unusual findings of leishmaniosis associated with circulating parasitised cells are described in four dogs. Most of the dogs presented severe illness, with lethargy, dysorexia, emaciation and alterations of the haematological pattern (anaemia, thrombocytopenia, neutrophilia and monocytosis). In three cases, leishmaniosis was associated with ehrlichiosis. On examination of peripheral blood smears, Leishmania sp. amastigotes were observed both in various circulating leukocytes (neutrophil, monocyte, macrophage) and free. In conclusion, parasites can rarely be detected in blood smears (in 0.28% of the animals examined); thus, the time-consuming microscopic search for amastigotes can make only a weak contribution to the conventional diagnosis of canine leishmaniosis.     

Cytologic patterns of lymphadenopathy in dogs infected with Leishmania infantum

BACKGROUND: Lymphadenopathy in canine leishmaniosis has been reported as reactive lymphoid hyperplasia or granulomatous (histiocytic) lymphadenitis. However, we are unaware of information on the effect of latent Leishmania infection on lymph node cytology compared with clinically affected dogs. OBJECTIVES: The aim of the present study was to investigate cytologic patterns of lymphadenopathy in dogs with clinical and subclinical forms of leishmaniosis and to correlate cytologic findings with the density of Leishmania amastigotes in fine needle aspiration (FNA) smears. METHODS: FNA cytology of prescapular or popliteal lymph nodes was evaluated on 32 dogs with clinical evidence of leishmaniosis (group A), 24 subclinically infected dogs (group B), and 17 clinically healthy noninfected dogs (group C); groups were based on the results of serologic and PCR tests for Leishmania sp. Differential nucleated cell counts (based on 300 cells) and amastigote density were determined microscopically. Cytologic findings were categorized and compared among groups. RESULTS: Cytologic abnormalities were found in 19 of 32 (59.4%) dogs in group A, 1 of 24 (4.2%) dogs in group B, and 2 of 17 (11.8%) dogs in group C and were significantly more frequent in group A than group B (P <.001) or C (P = .001). In group A, 68.7% of the dogs had lymphoid hyperplasia, 12.5% had lymphoid hyperplasia and histiocytic lymphadenitis, 6.3% had histiocytic lymphadenitis, and 3.1% had lymphoid hyperplasia and neutrophilic lymphadenitis. Lymphoid hyperplasia was also noted in 1 dog in group B, and lymphoid hyperplasia and eosinophilic lymphadenitis were each found in 1 dog in group C. Lymph node smears from 31 (96.9%) dogs in group A and 6 (25%) dogs in group B were positive for Leishmania amastigotes; however, no correlation was found between the density of amastigotes and cytopathologic patterns of lymphadenopathy. CONCLUSION: Abnormal lymph node cytology is much more common in dogs with clinical leishmaniosis than in dogs with subclinical infection, and primarily involves lymphoid hyperplasia. Despite finding no association between the density of amastigotes and type of lymphadenopathy, lymph node cytology still is a valuable diagnostic tool for diagnosing canine leishmaniosis.     

Canine leishmaniosis in Central Europe: retrospective survey and serological study of imported and travelling dogs

Canine leishmaniosis is a common parasitic disease in Central Europe affecting dogs imported or returning from endemic countries around the Mediterranean basin. Through an internet discussion forum owners of dogs with suspected or proven leishmaniosis living in Central Europe (D, A, CH), were questioned about the dog's history. Additionally, serologic examinations of the dogs for anti-Leishmania antibodies (ELISA using antigen of promastigote stages) were offered to the participants. From February to October 2003, 291 dogs imported or returning from Southern Europe (Spain, Italy, Greece, Turkey, France, Malta, Portugal and others) were analysed. Serologically, 111 dogs (38%) were classified positive; 103 being imported and eight travelling dogs. The majority of seropositive dogs originated from Spain (67%). No significant correlation could be established between race, sex and age and the incidence of the disease. The clinical symptoms in the seropositive dogs varied widely and ranged from mild general symptoms to visceral manifestations with chronic renal failure. Skin disorders were found in 78% of the seropositive, symptomatic animals. In the country of origin or after import or return, 174 out of 291 dogs (60%) had been tested for the presence of anti-Leishmania antibodies by different immunofluorescence antibody tests (IFAT). Discrepancies between the ELISA and the various IFATs used were noted in 55 cases (32%), especially in cases of low IFAT titers. Most of the seropositive dogs (80%) had been treated against leishmaniosis. In 91% of these cases, Allopurinol as monotherapy or in combination with Glucantime had been used. For diagnostics and therapy, dog owners had spent an average of 1,100 euros (median 900 euros, maximum 5,800 euros).     

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.     

Sporotrichosis: the main differential diagnosis with tegumentary leishmaniosis in dogs from Rio de Janeiro, Brazil

Seventy-four dogs from the State of Rio de Janeiro with ulcerated cutaneous lesions were submitted to clinical, dermatological, parasitological, mycological, histopathological and cytopathological exams, a leishmanin skin test, an indirect immunofluorescence (IIF) test for leishmaniosis, and nonspecific laboratory tests such as blood count and serum biochemistry. Sporothrix schenckii was isolated from 41 dogs and Leishmania (Viannia) braziliensis was isolated from 33 animals. Most dogs with sporotrichosis were from the municipality of Rio de Janeiro (53.7%) and presented ulcerated cutaneous lesions on the head (68.3%). Laboratory alterations in these animals included anemia (58.5%), hypoalbuminemia (83%) and hyperglobulinemia (75.6%). Histopathology revealed the predominance of a chronic granulomatous inflammatory infiltrate (70.7%), and yeast-like structures were detected in 17% of the histopathological exams and in 32% of the cytological exams. Three of 41 dogs with sporotrichosis were seropositive by IIF for leishmaniosis and 2 of 20 animals tested within this group had a positive leishmanin skin test. Similarly, most of the 33 dogs with leishmaniosis were from the municipality of Rio de Janeiro (69.7%) and had ulcerated cutaneous lesions on the head (84.8%). Laboratory alterations in these animals included anemia (66.7%), hypoalbuminemia (100%) and hyperglobulinemia (91%). Histopathology showed the predominance of a chronic granulomatous inflammatory infiltrate (63.6%) and amastigote forms were detected in 30.3% of the histopathological exams and in 31.8% of the 22 cytological exams performed. About 72.7% of the dogs were seropositive by IIF and five of seven animals had a positive skin test. Due to the clinical similarities, histopathological and nonspecific laboratory results similarities, the serological and skin tests for leishmaniosis positive in dogs with sporotrichosis, and the overlapping endemic areas in Rio de Janeiro, the differential diagnosis between the two diseases requires the demonstration of their respective etiological agents.     

Epidemiology of canine visceral leishmaniosis in the endemic area of Montes Claros Municipality,Minas Gerais State,Brazil

The Montes Claros City is located in an endemic area for visceral leishmaniosis in the Minas Gerais State, Brazil. With the implementation of a program for the control of visceral leishmaniosis in 1994, a sectional study was carried out to evaluate the infection by viscerotropic Leishmania in the population of dogs from Montes Claros, basically using indirect immunofluorescence antibody test (IFAT). Blood samples were collected on filter paper from 33,937 dogs, representing 96.1% of the canine local population. The prevalence for visceral leishmaniosis was found to be 9.7% in the municipality, being 9.9% in the urban area and 8.8% in the rural area. The annual incidence showed to be 64.3/1000 dogs. Prevalence of infection was not correlated with dogs age. The most affected breeds were: Boxer (24.6%) and Cocker (26.9%); Mongrel dogs had a prevalence of 7.8%. Short-hair animals had a prevalence of 11.9%, while long-furred animals had a prevalence of 8.9%. The isoenzymatic profile indicated that Leishmania (Leishmania) chagasi was the visceral leishmaniosis etiological agent in Montes Claros City, Minas Gerais State, Brazil. The main geographical areas for the parasite transmission were identified, and control measures were immediately started. The role of the dog as a reservoir for L. chagasi was confirmed. It was demonstrated that short-furred animals are at a higher risk of acquiring visceral leishmaniosis than the long-furred dogs.     

Characterization of lacrimal gland lesions and possible pathogenic mechanisms of keratoconjunctivitis sicca in dogs with leishmaniosis

In a previous study, it was found that 2.8% of dogs with leishmaniosis had keratoconjunctivitis sicca (KCS). The aim of this study was to characterize the lesions present in the lacrimal glands of dogs with leishmaniosis and to determine the presence of the parasite by means of immunohistochemistry. The inflammatory infiltrate was described as granulomatous or pyogranulomatous and was located around the ductal component of the glands. Immunoperoxidase staining localized the parasites following the same pattern. Samples from eyes that had clinical signs compatible with KCS presented inflammatory infiltrate and parasite more commonly than those from eyes without clinical signs. One of the mechanisms of KCS in dogs with leishmaniosis may be the inflammatory infiltrate located around the ducts of lacrimal glands, producing retrograde accumulation and retention of secretion. Meibomian gland was the most commonly affected by the infiltrate, highlighting the possibility of a qualitative KCS in these dogs.     

Feline leishmaniosis due to Leishmania infantum in Italy

A case of leishmaniosis in domestic cats (Felis catus domesticus) is described. The subject showed a nodular lesion on the eyelid. The diagnosis was achieved by serological, parasitological, and light and electron microscopic investigations. By molecular techniques the aetiological agent was identified as belonging to Leishmania infantum, the species implicated in human and canine leishmaniosis in southern Europe. A preliminary study on the prevalence of asymptomatic feline leishmaniosis, performed in the areas where the infected cat was identified, revealed a low seroprevalence of infection: only 1 (0.9%) of the 110 cat sera examined by indirect fluorescent antibody test was positive for anti-Leishmania antibodies. Because clinical signs in feline leishmaniosis are unspecific and similar to those observed in other diseases commonly found in this species, leishmaniosis must be added to the differential diagnosis by feline veterinary practitioners and adequate serologic and histopathologic investigations must be performed in endemic areas.     

Epidemiology of canine leishmaniosis in Catalonia (Spain) the example of the Priorat focus.

An epidemiological survey of canine leishmaniosis was conducted in the Priorat, a rural region in the Northeast of Spain, for 10 years (1985-1994). Seroprevalence throughout the region, determined by dot-ELISA and IFI, was 10.2% (8-12%). Forty percent of the dogs studied had a low level of anti-Leishmania antibodies, whereas only 50% were seronegative. Only one-third of the seropositive dogs had evident symptoms of the disease. Annual incidence of the disease was 5.7% and the level of endemicity was stable during the study. Four Leishmania zymodemes (MON-1, MON-29, MON-77, MON-105) were present in the focus, and their distribution in the different hosts is discussed. Apart from dogs and foxes, no other reservoir host has been found in the region.     

Comparison of different tissue sampling for PCR-based diagnosis and follow-up of canine visceral leishmaniosis

In this study, different types of tissue sampling for PCR-based diagnosis and follow-up of canine visceral leishmaniosis were compared. Skin, whole blood and lymph node samples were collected from 95 naturally infected dogs living in South Italy, where the disease is endemic. Twenty-nine of these 95 dogs, treated with meglumine administered concurrently with allopurinol for 30 days, and then with allopurinol alone, were monitored during a period of 2 years. The DNA extracted from the clinical specimens was amplified by PCR using as target DNA a 116-bp fragment in the constant region of the kinetoplast DNA minicircle. PCR analysis was more sensitive than indirect immunofluorescence antibody test in detecting Leishmania infection in symptomatic dogs: 99% of lymph node samples resulted positive, whereas 94% of blood samples and 95% of skin samples gave a positive result. PCR analysis of samples from dogs followed up 2 years showed that: (1) all subjects resulted positive in at least one of the three types of samples; (2) all time the dogs had a relapse, PCR resulted positive in all three types of samples; (3) when dogs were apparently healthy, PCR analysis was positive on skin and lymph node samples, but not always on blood samples. Since lymph node sampling is invasive and sometimes difficult in healthy asymptomatic dogs, our results suggest that, independently from the presence or not of cutaneous lesions, skin biopsy represents a good substratum for PCR-based diagnosis and follow-up of canine visceral leishmaniosis.     

Seroepidemiology of Bartonella vinsonii subsp berkhoffii exposure among healthy dogs

OBJECTIVE: To determine seroprevalence of antibodies to Bartonella vinsonii subsp berkhoffii and risk factors for seropositivity among working dogs owned by the US government. DESIGN: Cross-sectional study. ANIMALS: 1,872 dogs. PROCEDURE: An ELISA was used to detect antibodies to B vinsonii subsp berkhoffii. RESULTS: Antibodies to B vinsonii subsp berkhoffii were detected in 162 dogs (8.7%; 95% confidence interval, 7.4 to 10.0%). Dogs living in the southeast, plains states, southwest, and south-central were significantly more likely to be seropositive than were dogs living in other regions of the United States. German Shepherd-type dogs were significantly less likely to be seropositive than were dogs of other breeds, and dogs entering training programs or that had been rejected from a training program were significantly more likely to be seropositive than were dogs used for narcotics detection and dogs trained to patrol or detect explosives. Dogs used by the border patrol or Federal Aviation Administration were more likely to be seropositive than were dogs used by the Department of Defense or customs service. Odds that dogs would be seropositive were significantly higher for dogs stationed in the southern United States, the northeastern United States, or a foreign country, compared with dogs stationed in all other regions of the United States. CONCLUSIONS AND CLINICAL RELEVANCE: Overall, 8.7% of this diverse group of healthy dogs was found to be seropositive for antibodies to B vinsonii subsp berkhoffii, and seropositivity rates were associated with location, suggesting either that there are multiple vectors for the organism or that the major vector for the organism depends on geographic and environmental factors.     

The Ibizian hound presents a predominantly cellular immune response against natural Leishmania infection

Veterinarians working in the Balearic Islands (Mallorca), an endemic region of canine leishmaniosis, have reported very few cases of leishmaniosis in Ibizian hounds while concurrently observing that dogs of other breeds had a high incidence of clinical canine leishmaniosis. To further investigate this observation, two populations of dogs from the Balearic Islands were examined for the presence of Leishmania-specific cellular immunity using a delayed type hypersensitivity test (DTH) to leishmanin and for the presence of Leishmania-specific humoral immunity using an ELISA. Fifty-six asymptomatic dogs, 31 Ibizian hounds and 25 dogs belonging to other breeds were examined. Seventy-seven percent of the dogs demonstrated a specific immune response against Leishmania, either humoral or cellular. This finding suggests that the infection rate (77%) was higher than previously considered. For Ibizian hounds 81% were DTH positive while only 48% of the other dogs were DTH positive. A statistical association between Ibizian hounds and positive DTH response was found. A specific humoral response was found in 48% of Ibizian hounds and in 56% of the other dogs. No statistical association relative to the Leishmania-specific IgG1 and IgG2 levels were found between the two groups. The Ibizian hound has been reported to be more resistant to Leishmania infection and we found that the Ibizian hound mounts a significant cellular response to infection. Thus, the Ibizian hound may be an interesting canine model for the investigation of protective anti-Leishmania immune response.     

Canine visceral leishmaniasis in urban and rural areas of Northeast Brazil

The purpose of this study was to determine the clinical and laboratory profiles of canine leishmaniasis in two distinct areas. Dogs from urban and rural areas were examined. The population studied in the metropolitan area included 54 dogs. Of these, 20 (37%) animals did not present with any signs suggestive of visceral leishmaniasis (VL). Among these, only eight were confirmed negative by ELISA (rK39 and CE) and 12 dogs, clinically negative for leishmaniasis, were seropositive by ELISA (rK39 and CE). Thinness, conjunctivitis and onychogryphosis were the most frequent clinical signs in the urban areas, followed by crusty lesions, alopecia, ulcerated lesions, hyperkeratosis and exfoliation. In the metropolitan area human VL cases occurred mainly in 1991, 1992, 1999 and 2000. In the rural areas the ELISA rK39 test detected a seroprevalence of 11.3% and ELISA CE (Leishmania crude extract) of 20.6%. Thirty-nine dogs were examined 6 months after the first visit. Serological exams using rK39 antigen showed seroconversion of only one dog, whereas Leishmania CE showed seroconversion of 13 (33.4%) dogs. In this rural environment 83.3% of the positive dogs were asymptomatic. Lutzomyia intermedia and Lu. longipalpis were the most predominant sandfly vector species. Amastigotes were identified in spleen and liver fragments of symptomatic necropsied animals. PCR amplification of DNA isolated from promastigote culture indicated that the species was Leishmania chagasi. This finding suggests that delayed diagnosis and euthanasia of potentially infectious animals may occur with an increased transmission risk to sandflies and subsequently to humans.