Canine Visceral Leishmaniasis In Dogs Research Articles

Environmental Variables Associated with Distribution of Canine Visceral Leishmaniasis in Dogs in Ardabil Province, Northwestern Iran: A Systematic Review

Background: Visceral leishmaniasis (VL) is a zoonotic disease that currently occurs in some parts of Europe, Asia, Africa, and America. This study aimed to determine the distribution of the canine visceral leishmaniasis in dogs (Canis lupus familiaris) in northwestern Iran.
 Methods: The data were collected from 1994 to 2018 in Ardabil Province from electronic databases. An extensive literature search was conducted in different international and national databases, including Cochrane, MEDLINE/PubMed, Scopus, Web of Science, and Iran Medex to find articles with the words “visceral leishmaniasis in Ardabil” in their titles, and “canine visceral leishmaniasis in Ardabil” or “accidental reservoir hosts of visceral leishmaniasis in Ardabil” in their subtitles, irrespective of the type and duration of study. The GIS software and MaxEnt model were used to determine the ecologically suitable niches for the disease.
 Results: In total, 9088 dogs were examined, and the overall prevalence rate of CVL in dogs was estimated to be 14.56%. The most ecologically suitable areas of CVL occurrence were identified in four hotspots in Meshkinshahr, Germi, and two spots in Parsabad counties. The results of jackknife test showed that the environmental and climate variables with the highest gain, when used in isolation, were Isothermality, Bio3, Bio13, and Bio 4.
 Conclusion: A widely epidemic CVL has emerged among dogs, making a lot of risks on inhabitants of this area and increasing the probability of an outbreak of VL in humans.

Seroepidemiology of Leishmania infantum in dogs in the city of Porto Alegre, Rio Grande do Sul, Brazil

Leishmaniosis are zoonoses that present several clinical manifestations in humans and have dogs as their main reservoir in the urban environment. Visceral leishmaniasis (VL) is the most severe form of the parasitosis and has been increasing in Brazil, despite the actions of public health agencies. Until 2002, the State of Rio Grande do Sul (RS) was considered free of human and canine leishmaniasis. The first human case of cutaneous leishmaniasis in RS was recorded in 2003. In 2009, the first autochthonous cases of human VL and canine visceral leishmaniasis (CVL) were confirmed in São Borja, RS, and the occurrence of the insect vector was recorded for the first time in the state. In 2010, the first confirmed case of CVL was reported and seropositive dogs were identified in the city of Porto Alegre, RS. Given the importance of this zoonosis and the difficulties of a reliable diagnosis in dogs, this study aimed to identify epidemiological aspects of CVL in dogs in an area of Porto Alegre where cases of the disease have been reported. A total of 300 blood samples were collected from dogs in this area, which were then tested by the methods of RT-DPP® and ELISA for diagnosis of Leishmania infantum. An epidemiological questionnaire was completed by dog owners, containing aspects related to care of the animals, characteristics of their environment, and their living conditions. We observed that 83% (250/300) of the studied dogs were of mixed breed, 58% (175/300) were female, 78% (238/300) slept outdoors, and 61% (183/300) shared their living quarters with other species. Clinically, we observed that 90% (270/300) of the animals were infested by ectoparasites, 70% (210/300) had dermatopathies, 24% (72/300) presented weight loss and anorexia, and 22% (65/300) had ocular disorders. The results of the two serological tests were 100% concordant for the three seropositive samples (1%), and the remaining 297 (99%) were negative for both tests. We conclude that despite the low prevalence of L. infantum seropositive dogs, conditions in the region are favorable for CVL transmission, creating a risk of VL for the human population in the city of Porto Alegre.

Performance of an indigenous β-mercaptoethanol-modified antigen in comparison with a commercial reference in direct agglutination test for detection of canine visceral leishmaniasis

We compared the performance of a locally produced β-mercaptoethanol-modified promastigote antigen (β-ME-Ag) of an indigenous Leishmania infantum strain against that of a trypsinized Leishmania donovani reference (REF-Ag) in the direct agglutination test (DAT) for detection of canine visceral leishmaniasis (CVL). One hundred and fifty-one serum samples collected from dogs belonging to four groups with different conditions were included. At a DAT titre of 1 : 320, statistically determined as optimal cut-off value for β-ME-Ag, and 1 : 160 for REF-Ag, a sensitivity and a specificity of 100 % were estimated for β-ME-Ag in comparison with 96.6 % and 100 %, respectively, for REF-Ag. Overall, levels of agglutination titres recorded for the two antigens were highly concordant (Cohen's κ = 0.879) in both the CVL and non-CVL groups. Based on current results, and ease experienced in processing the antigen and reading the test outcome, we recommend incorporation of β-ME-Ag in DAT for confirmation or exclusion of suspected CVL in dogs.

Longitudinal analysis of serological tests officially adopted by the Brazilian Ministry of Health for the diagnosis of canine visceral leishmaniasis in dogs vaccinated with Leishmune®

Development of vaccines against canine visceral leishmaniasis (CVL) may provide a prophylactic barrier, but antibody response detected by standard diagnostic techniques may not separate vaccinated from naturally infected dogs. Moreover, anti-Leishmania antibody levels in vaccinated dogs may be detectable for months. Accordingly, the aim of the present study was to comparatively evaluate an “in-house” ELISA with three serological tests officially adopted by the Brazilian Ministry of Health for the diagnosis of CVL in dogs vaccinated with Leishmune®. A total of 18 mongrel dogs were submitted to a complete protocol of the vaccine, monitored and evaluated in 5 times (T0–T4) up to 180 days after T0. Twenty-one days after the first dose (T1), 50% of the dogs were seropositive by the “in-house” ELISA and 5.5% by IFAT, while by the official ELISA and DPP® CVL rapid test all dogs tested negative. At time T2, 42 days after of the first dose, 100%, 83.3%, 11.1%, and 5.5% of the dogs were seropositive by the “in-house” ELISA, IFAT, official ELISA kit and the DPP® CVL rapid test, respectively. Ninety days after the first dose (T3), 100%, 83.3%, 72.2% and 33.3% of the dogs were seropositive by the “in-house” ELISA, official ELISA kit, IFAT, and the DPP® CVL rapid test, respectively. Finally, at time T4, 88.8%, 33.3%, 11.1% and 5.5% of the dogs were seropositive by the “in-house” ELISA, official ELISA kit, DPP® CVL rapid test and IFAT, respectively. In conclusion, dogs vaccinated with Leishmune® cross-react by an “in-house” ELISA and by the three official Brazilian serological tests for the diagnosis of canine visceral leishmaniasis up to six months after the first vaccine dose, and may be mistakenly diagnosed and removed.

Foco de leishmaniasis en El Hobo, municipio de El Carmen de Bolívar, Bolívar, Colombia

The epidemiological characteristics and the importance of the Lutzomyia species present in a leishmaniasis focus in the village El Hobo, Carmen de Bolívar, Department of Bolivar, Colombia, are described. To obtain a preliminary assessment of leishmaniasis transmission in the village of El Hobo, Carmen de Bolívar. Epidemiological data were analyzed and sandflies were collected with CDC traps and on protected human volunteers in the village of El Hobo. Sero prevalence of canine visceral leishmaniasis in dogs was evaluated using indirect inmunofluorescence (IFAT). Nine Lutzomyia species were collected: L. trinidadensis, L. evansi, L. cayennensis, L. venezuelensis, L. gomezi, L. dubitans, L. ylephiletor, L. yuilli, and L. walkeri. The species of greater importance based on their implication in the transmission of cutaneous and visceral leishmaniasis were L. gomezi, and L. evansi respectively. Specimens of L. venezuelensis, L. dubitans, L. ylephiletor, L. yuilli, and L. walkeri are reported for the first time for the Department of Bolivar. The sero prevalence of visceral leishmaniasis in dogs was 36%. According to the epidemiological records, in 2002 the municipality of Carmen de Bolivar presented a 40% increase in cases of cutaneous leishmaniasis and an 80% increase in canine visceral leishmaniasis as compared to 2001, due to the outbreak in the village of El Hobo. The results indicate that the village of El Hobo is an area of potential risk for transmission of both cutaneous and visceral leishmaniasis.

Serological survey and comparison of two polymerase chain reaction (PCR) assays with enzyme-linked immunosorbent assay (ELISA) for the diagnosis of canine visceral leishmaniasis in dogs

Visceral leishmaniasis (VL) is systemic zoonotic parasitic infection that is a health problem in some tropical and subtropical countries. The purpose of our study is to determine the seroprevalence of canine visceral leishmaniasis (CVL) in owned dogs of the Sarab area and to identify the species of Leishmania isolated from these dogs. We also compared the sensitivities and specificities of two polymerase chain reaction (PCR) assays (kDNA and ITS1) used for Leishmania infantum identification with culture, microscopic detection and enzyme-linked immunosorbent assay (ELISA) methods as well as validate the PCR techniques for the molecular diagnosis of CVL. Sera from 384 dogs of 30 villages around Sarab, were tested by ELISA and buffy coat blood fractions after sampling tested with PCR by specific primers (kDNA, ITS-18sRNA). Thirty-five dogs were seropositive by ELISA. The seroprevalence rate (SPR) of CVL was 9.1% (CI, 95% 6.6 -12.4). The most important serological result was a high proportion of seropositivity for leishmaniasis. Out of 361 (94%) asymptomatic dogs, 31 (8.6%) were seropositive, and out of 23 (6%) symptomatic dogs, 4 (17.4%) were seropositive. Agreement between the ELISA test and clinical signs was 86.7%. Each assay was performed on 60 blood samples. PCR of kDNA (7/60 positives, 11.8%) was the most sensitive of the assays examined, followed by ELISA (3/60, 5%) and ITS1-PCR (2/60, 3.4 %). All diagnostic assays were highly specific (100 %) and had positive predictive values (PPV) >90% and negative predictive values (NPV) >88% for CVL. As expected, kDNAPCR proved to be the most sensitive (87.5 %) assay for leishmanial DNA in peripheral blood. This study shows that kDNA-PCR is significantly more sensitive than the other parasitological and serological methods, allowing the identification of infected dogs even before the appearance of serum L. infantum antibodies. Because kDNA-PCR is the most reliable, sensitive, and also a rapid diagnostic assay for CVL, it should be employed as the new standard for routine diagnosis. Key words : Leishmania infantum, polymerase chain reaction, kinetoplast DNA, enzyme-linked immunosorbent assay, Visceral leishmaniasis, dogs, prevalence.

Validation of a Leishmania infantum ELISA rapid test for serological diagnosis of Leishmania chagasi in dogs

Canine visceral leishmaniasis (CVL) is caused by Leishmania donovani complex parasites including L. donovani, Leishmania infantum and Leishmania chagasi. As some studies suggest that L. chagasi and L. infantum may be very similar or even the same species, the aim of the present study was to evaluate a commercial rapid ELISA test, originally designed for L. infantum, in the diagnosis of CVL in dogs naturally infected by L. chagasi. A total of 400 serum canine samples, including 283 positive dogs for CVL from an endemic area, 86 clinically healthy dogs from a non-endemic area and 31 dogs seropositive for confounding infectious agents (Trypanosoma cruzi, Toxoplasma gondii, Neospora caninum, Babesia canis and Ehrlichia canis) were used for test validation. An overall sensitivity of 94.7% (95% CI=91.41–97.01%) and specificity of 90.6% (95% CI=83.80–95.21%) was found, with a high degree of agreement (k=0.8445) to the indirect ELISA. When confounding infectious diseases were excluded, specificity increased to 100% (95% CI=95.8–100%), with a higher degree of agreement (k=0.8928). In conclusion, the commercial kit designed for L. infantum was a highly sensitive and specific device for detection of L. chagasi infection in dogs, which indicates high immunoreactivity similarities between L. infantum and L. chagasi.