Prevalence Of Canine Leishmaniasis Research Articles

New Microsatellite Markers for Genetic Studies on Sergentomyia schwetzi (Diptera: Psychodidae): A Suspected Vector of Leishmania infantum (Trypanosomatida: Trypanosomatidae) in the Canine Leishmaniasis Focus of Mont-Rolland, Senegal.

Visceral leishmaniasis is not endemic in West Africa, but prevalence of canine leishmaniasis and seroprevalence of Leishmania infantum infection in humans are high in the Mont Rolland community (Thiès region, Senegal). Previous studies in this area showed that Sergentomyia schwetzi could be the potential vector of Le. infantum. To precisely describe the biology and population structure of this potential vector, we identified eight novel microsatellite loci to characterize Se. schwetzi populations. We tested these loci in Se. schwetzi populations from five locations at Mont Rolland (Thiès, Senegal). All the loci were polymorphic, with a mean of 17.25 alleles (observed heterozygosity: 0.455). We did not detect any evidence of scoring errors due to stuttering and large allele dropout. Moreover, several of these loci were also amplified in six other sand fly species (Sergentomyia magna, Sergentomyia dubia, Sergentomyia minuta, Phlebotomus duboscqi, Phlebotomus perniciosus, and Phlebotomus ariasi). These preliminary results demonstrate the utility of these microsatellite markers for Se. schwetzi (and for the other sand fly species) population genetic studies.

Canine Leishmaniasis Prevalence in the Slovenian Dog Population.

IntroductionLeishmaniasis is a life-threatening zoonosis of which dogs are the major reservoir and sandflies are the vectors. Until now, the prevalence of canine leishmaniasis (CanL) in the Slovenian dog population was unknown.Material and MethodsEpidemiological data, eye swabs and blood samples were taken from 465 dogs born in Slovenia and older than one year. Commercial ELISA kits and real-time PCR were used. For ELISA-positive samples, an immunofluorescence antibody test (IFAT) was performed. Descriptive statistics were used to characterise the samples. The one-sample nonparametric chi-square test was used to test whether the categories of a variable were equally distributed.ResultsA 59.9% proportion of the recruited dogs had travelled to endemic regions and 62.1% of them had not been protected by insect repellents. Skin symptoms that might be CanL-related were described in 109 of the dogs’ histories (23.4%), inappetence and/or weight loss in 25 (5.4%), and anaemia, intermittent fever, and/or lymphadenopathy in 19 (4.1%). At the time of recruitment, all dogs were asymptomatic. All samples were PCR negative, nine (1.9%) were ELISA positive, but none were IFAT positive. Five of the nine ELISA-positive dogs were non-travellers.ConclusionWe conclude that the seroprevalence of canine leishmaniasis of 1.9 % in the autochthonous Slovenian dog population may pose a risk of endemic spread of the disease.

Leishmaniasis due to Leishmania infantum: Integration of human, animal and environmental data through a One Health approach.

The aim of this study was to explore Leishmania infantum epidemiology through a One Health approach that promotes a better estimation of leishmaniasis burden and a deeper understanding of the spatial distribution of the key actors of the parasite life cycle (vectors, reservoirs and humans). We conducted a 14-year mixed retrospective and prospective study of leishmaniasis cases in an endemic area in southern Spain (Granada province), to estimate the human incidence and its association with the vector presence, cryptic leishmaniasis rates and canine leishmaniasis prevalence. We found an annual linear increase in the incidence that cannot be fully explained by active case surveillance and the improvement of PCR diagnostic techniques. 49.4% of cases were not reported to the surveillance system. Approximately half of the human cases correspond to the visceral form that occurred more frequently in men; cutaneous, mucosal and cryptic forms were also detected. Leishmaniasis is no longer a disease of young children, accounting for a quarter of immunocompetent patients and most infected people remained asymptomatic. Human and canine leishmaniasis, cryptic or symptomatic, are present in the whole province, where there is a medium/high risk of the presence of Phlebotomus perniciosus, the main vector. We found association between the incidence of human leishmaniasis and the presence of the vector, but not with the prevalence of canine leishmaniasis and cryptic human leishmaniasis. A potential hot spot was also found, where high leishmaniasis incidence may be associated to the involvement of host species other than dogs.

Seroprevalence of Leishmaniasis Among Dogs Living in a Municipal Dog and Cat Shelter in Edirne.

In this study, we aimed to investigate the seroprevalence of canine leishmaniosis among dogs that live in the town center due to a lack of data on the prevalence of canine leishmaniasis (CanL) in Edirne. In the present study, 37 dogs living in a municipal dog and cat shelter in Edirne were screened for leishmaniosis by the ındirect fluorescent antibody test. All samples were found to be seronegative. Our study is a preliminary study for Edirne. We wish to perform a large-scale seroepidemiological study with a larger number of dogs from different regions and identify Phlebotomus species.

Prevalence and Associated Factors of Canine Visceral Leishmaniasis in an Endemic Area of Mato Grosso, Brazil

Background: Canine visceral leishmaniasis is a chronic and severe disease of great interest to global public health. In Brazil, the main species causing visceral leishmaniasis is Leishmania chagasi [syn. Leishmania infantum], which is transmitted by sandflies of the species Lutzomyia longipalpis and Lu. cruzi. This study aimed to determine the risk factors and prevalence of visceral leishmaniasis in dogs residing in endemic areas of the municipality of Várzea Grande, Mato Grosso.Material, Methods & Results: The study was conducted in the Várzea Grande neighbourhoods Jardim Eldorado, Parque Sabiá and São Mateus, which are located in the Brazilian Cerrado region and are endemic for visceral leishmaniasis. The Várzea Grande is a mostly commercial and industrial municipality and relies on subsistence farming. To describe the general characteristics of the dog population and housing environment, an interview was carried out with the dog owners in each household. This interview addressed local demographics and the identification of dogs to establish epidemiological aspects of canine illness and risk factors for infection. The dogs were examined and physically restrained for blood collection by jugular venipuncture. For serological testing, a commercial enzyme-linked immunosorbent assay (ELISA) was used. A Chi-square test or Fisher’s exact test was used to identify associations between independent variables and the seroprevalence of dogs with anti-Leishmania antibodies. It were collected blood from 521 animals, including 160 belonging to Jardim Eldorado, 129 to Parque Sabiá and 232 to São Mateus. Of these animals, 120 were reactive by ELISA, with a prevalence of 23.0%. There was no statistically significant difference (P > 0.05) according to gender, age, racial definition, origin, time with family, presence of ectoparasites, or the presence of people with skin wounds at home or on other pets. The major risk factor for canine infection was fur length; dogs with short fur were 2.2 times more likely to be infected than dogs with long fur.Discussion: The prevalence of canine leishmaniasis in endemic areas was found to be similar to studies in Cuiaba, a city in Várzea Grande, which also included neighbourhoods endemic for visceral leishmaniasis as study areas. Other studies have shown prevalence rates that differ from those found in this study. This difference may either be because the neighbourhoods in this study had already experienced outbreaks of the disease or because serum samples were cross-reactive with other trypanosomatids. While infection was more readily detected in dogs with clinical signs, asymptomatic dogs with anti-Leishmania antibodies were found in greater numbers, which is consistent with the literature. Hair length was the only factor associated with canine leishmaniasis in this study; short-haired animals were most at risk of contracting the disease because they had more skin exposure to sandflies during blood feeding. In conclusion, endemic districts of Várzea Grande had high prevalence rates of canine visceral leishmaniasis, and a short length coat was associated with infection.

Performance of a real time PCR for leishmaniasis diagnosis using a L. (L.) infantum hypothetical protein as target in canine samples

Visceral leishmaniasis represents an important public health issue in different parts of the world, requiring that measures be put in place to control the spread of the disease worldwide. The canine leishmaniasis diagnosis is not easy based on clinical signs, since dogs may not develop the infection with recognizable signs. Thus, the laboratorial diagnosis is essential to ascertain the incidence and prevalence of canine leishmaniasis especially in areas with major control efforts. Although, the diagnosis can be performed by the use of different approaches, the molecular methods such as PCR have become an indispensable tool for leishmaniases diagnosis. A TaqMan assay for real-time PCR (Linj31-qPCR) was developed to determine the parasite occurrence in clinical cases of leishmaniasis. The assay targets an L. (L.) infantum hypothetical protein region. The specificity of the assay was verified by using Leishmania World Health Organization reference strains including parasites belonging to subgenus L. (Leishmania), subgenus L. (Viannia), other Leishmania species and Trypanosoma cruzi. The sensitivity was verified by using isolates of L. (L.) amazonensis and L. (L.) infantum. The usefulness of the assay for diagnosis was ascertained by testing 277 samples from dogs in regions endemic for visceral and/or cutaneous leishmaniasis and from regions in which leishmaniasis was not endemic in São Paulo State, Brazil. Diagnosis of canine visceral leishmaniasis (CVL) was determined on these animals by conventional PCR and three serological tests. The dog samples were divided into four groups. I, dogs with CVL (n = 101); II, dogs with other diseases and without CVL (n = 97); III, dogs with American cutaneous leishmaniasis (n = 7), and, IV, dogs without CVL (n = 72) from areas where leishmaniasis was not endemic as control group. Results indicated that Linj31-qPCR was able to identify parasites belonging to subgenus L. (Leishmania) with no cross-amplification with other parasite subgenera. The Linj31-qPCR detected Leishmania parasites DNA in 98% of samples from Group I. In conclusion this methodology can be used as routine diagnostic tools to detect parasites from subgenus Leishmania.

Seroprevalence of canine leishmaniasis in Kwara, Oyo and Ogun states of Nigeria.

Leishmaniasis is an important tropical disease that is gradually gaining attention in Nigeria. The canine species which include domestic dogs have been named the reservoir host for the zoonotic form of leishmaniasis. The present study was carried out to determine the seroprevalence of canine leishmaniasis in three selected states of Nigeria using indirect enzyme linked immunosorbent assay (ELISA). Two hundred and seventy-three canine sera were tested for Leishmania IgG antibodies. Dogs sampled were grouped into young (<1year) and adult (>1year). Total prevalence recorded was 4.40% (12/273). There was no significant difference (P>0.05) between sera of hunting (4.83%) and companion dogs (3.03%). Furthermore, there was no significant difference (P>0.05) between young and adults dogs. There was no correlation between sex and prevalence of canine leishmaniasis. However, significant difference (P<0.05) was observed in the prevalence of each state with Kwara, Oyo and Ogun having 14.63, 3.33 and 1.32% respectively. The result of this study established the presence of canine leishmaniasis in Oyo, Ogun and Kwara States of Nigeria making the zoonotic form of the disease a possibility.

Kuzey Kıbrıs'ta Kanin Leishmaniasis ve Kum Sineklerinin Epidemiyolojisi

In this study, the investigation on the prevalence of canine leishmaniasis (CanL) and sand fly species incriminated as potential vectors of leishmaniasis in the northern part of the Cyprus were aimed. This research was conducted in two periods; 2004 and 2012. Serological (IFAT and rK39) and molecular (PCR) tests were performed on 83 dog blood samples during the 2004 survey. PCR was performed using primers 13A/13B targeting kinetoplastid minicircle constant region. Genomic Nested-PCR was applied using R221/R332 and R323/333 primers for 5 clinically suspected dog samples in 2012. Sand flies were collected from the Lapithos town and Kyreniae province using CDC light traps and midgut dissection was done for the presence of Leishmania parasites during the 2012 survey. Three (3.61%) out of 83 dogs were found to be positive for CanL in 2004, while 3 out of 5 clinically suspected dogs were positive in 2012. In total 296 female sand flies were dissected and 9 species belonging to Phlebotomus and Sergentomyia genera were determined. No promastigote was found in the dissected females. The results obtained in two different periods showed that the importance and risk of canine disease are increasing in the northern Cyprus and further studies should be performed in northern Cyprus for determining the incidence of canine and human leishmaniasis.

Surveillance of leishmaniases in France, 1999 to 2012

Leishmaniasis is endemic in the south of France, where autochthonous disease is caused by Leishmania infantum, and affects both humans and dogs. The prevalence of canine leishmaniasis is between 3 and 66% depending on the region and the methods used. Human leishmaniases are also imported into France, mainly from French Guiana and North Africa. The surveillance of autochthonous and imported human leishmaniases is based on passive notification to the National Reference Centre for Leishmaniases (NRCL) created in 1998. Between 1999 and 2012, 317 autochthonous and 1,154 imported cases were notified to the NRCL. The average number of autochthonous cases notified per year was 22.6, mainly cases of visceral leishmaniasis (84.5%). All cases were infected in the south of France. Leishmaniasis incidence is 0.22 per 100,000 inhabitants in the endemic area. Imported cases were more frequent (annual mean of 82.4 cases) and consisted predominantly in cutaneous leishmaniasis (CL) cases (91%), essentially L. major CL imported from Maghreb and Sub-Saharan Africa, and L. guyanensis CL from French Guiana. This national notification system allowed a better understanding of the incidence and distribution of the disease; it is also useful to assess the temporal-spatial evolution of the disease in France, which appears relatively stable.

Surveillance of leishmaniases in France, 1999 to 2012

Leishmaniasis is endemic in the south of France, where autochthonous disease is caused by Leishmania infantum, and affects both humans and dogs. The prevalence of canine leishmaniasis is between 3 and 66% depending on the region and the methods used. Human leishmaniases are also imported into France, mainly from French Guiana and North Africa. The surveillance of autochthonous and imported human leishmaniases is based on passive notification to the National Reference Centre for Leishmaniases (NRCL) created in 1998. Between 1999 and 2012, 317 autochthonous and 1,154 imported cases were notified to the NRCL. The average number of autochthonous cases notified per year was 22.6, mainly cases of visceral leishmaniasis (84.5%). All cases were infected in the south of France. Leishmaniasis incidence is 0.22 per 100,000 inhabitants in the endemic area. Imported cases were more frequent (annual mean of 82.4 cases) and consisted predominantly in cutaneous leishmaniasis (CL) cases (91%), essentially L. major CL imported from Maghreb and Sub-Saharan Africa, and L. guyanensis CL from French Guiana. This national notification system allowed a better understanding of the incidence and distribution of the disease; it is also useful to assess the temporal-spatial evolution of the disease in France, which appears relatively stable.

Epidemiological implications of the use of various methods for the diagnosis of canine leishmaniasis in dogs with different characteristics and in differing prevalence scenarios

Our aim was to establish the influence on the prevalence of canine leishmaniasis (CanL) of the following: (1) the use of different diagnostic techniques; (2) different positivity thresholds; (3) selection of animals either at random from a population or focused on symptomatic individuals, (4) the function which the dog performs; and (5) scenarios with differing epidemiological characteristic. Three groups of dogs were analysed (416 sampled at random from an endemic area, 71 with symptomatology compatible with CanL and 15 from a non-endemic area) using three serological techniques (indirect fluorescence antibody test (IFAT), Kalazar Detect(TM) and Q Letitest ELISA) and a PCR-ELISA. The diagnostic technique had a considerable influence on the CanL prevalence value obtained. Uncertain antibody titres were more representative in dogs sampled at random and with the IFAT technique. Although employing different capture antigens, correlation of results was higher between the two commercial techniques in the group of dogs with symptomatology compatible with CanL. The sensitivity and specificity values of the different diagnostic techniques were affected by the epidemiological characteristic of the area under study, the presence of clinical signs and the function which the dog performs. This must be taken into account when comparing endemicity in different geographical areas, such as in studies carried out for the construction of risk maps. Using more than one technique, and adopting the criterion of considering an animal to be positive only when it has been diagnosed as such by more than one technique, considerably raises the prevalence values but maintains the differences between areas with different characteristics.

Increase in the prevalence of canine leishmaniasis in urban Algiers (Algeria) following the 2003 earthquake

Between 2005 and 2008, a serological survey for leishmanial infection was conducted among dogs from urban and peri-urban Algiers, with the focus on the new, densely populated areas that were built after the 2003 earthquake. Serum samples were collected from 1810 animals and tested for the presence of leishmanial antibodies by IFAT, ELISA and western blotting. The overall seroprevalence recorded was 25.1%. Of the seropositive dogs, 58.8% showed no clinical signs of the disease, 25.8% had a few, minor signs and the remaining 15.4% showed more severe illness. The major clinical signs of infection were weight loss, skin lesions and lymphadenopathy. Although seropositive dogs were found in all of the boroughs (daïras) of Algiers, seroprevalences were highest in the western part of the city (i.e. in the boroughs of Bouzaréah, Chéraga and Zéralda), ranging from 23.0% to 44.5%. Statistical analysis showed a relationship between seropositivity for leishmanial infection and the dog's age and lifestyle (i.e. whether the dog lived outside and/or in areas with dense vegetation). Only two zymodemes were identified amongst the 50 isolates investigated: MON-1 (88%) and MON-281 (12%). The latter zymodeme has not been previously found in Algeria, sandflies or dogs.

Prevalence of Leishmania infantum infection in dogs living in an area of canine leishmaniasis endemicity using PCR on several tissues and serology.

We studied and compared the prevalence of Leishmania infection and the seroprevalence and the prevalence of canine leishmaniasis in an area where canine leishmaniasis is endemic. One hundred dogs living on the island of Mallorca (Spain) were studied. In this study, we clinically examined each dog for the presence of symptoms compatible with leishmaniasis, determined the titer of anti-Leishmania antibodies, and investigated the presence of Leishmania DNA by PCR in skin, conjunctiva, and bone marrow samples of each dog. The prevalence of the disease and the seroprevalence were 13 and 26%, respectively. In 63% of the dogs, Leishmania DNA could be detected by PCR in at least one of the tissues studied. The results of positive PCR in the bone marrow, the conjunctiva, and the skin were 17.8, 32, and 51%, respectively. The prevalence of the infection, 67%, was calculated using all animals that were seropositive and/or positive by PCR with any tissue. The results showed that the majority of dogs living in an area where canine leishmaniasis is endemic are infected by Leishmania and that the prevalence of infection is much greater than the prevalence of overt Leishmania-related disease.

Canine leishmaniasis. New concepts of epidemiology and immunopathology: their impact in the control of human visceral leishmaniasis

Visceral leishmaniasis (VL) is a zoonosis in most regions where it occurs. Dogs are the most important reservoir of the disease and are mainly responsible for the persistence of VL in the Paleartic and Neotropical regions. Canine leishmaniasis (CaL) is a viscerocutaneous, chronic infection with a worse prognosis than human disease. We now know that, as in man, there are some cases of asymptomatic infection. Former studies indicated that dog cutaneous parasitism becomes infectious to the insect vector in later periods of the disease, but recent studies performed by xenodiagnosis have shown that it is possible that transmission might occur earlier. The infected animal reacts with a great production of antibodies and depression of cellular immunity. Antibodies are not protective and resistance is related with active cellular immunity. The presence of Th 1 response in asymptomatic animals, sometimes without humoral response, means that the prevalence of CaL, found in epidemiological surveys by searching for antibodies, may be underestimated.

The life expectancy of phlebotomine sandflies: first field estimates from southern France.

1. A field study of Phlebotomus ariasi Tonnoir, the vector of Leishmania infantum Nicolle in southern France, addressed the following questions: Is it possible to estimate reliably the life expectancy of this sandfly; can spatial or temporal variation in the life expectancy be detected, and is such variation significant for disease transmission? 2. Life expectancy was estimated by examining follicular relics in the ovaries of more than ten thousand females caught in light traps at seven sites in the Cévennes and the Garrigues, throughout their active period in 1985 and 1986. Whilst the distinction between nulliparous and parous flies was easily made, assessments of the number of times a parous fly had laid eggs were unreliable. Best estimates of life expectancy were therefore calculated from the parous rate. 3. Large samples collected from one site in the Cévennes in both years gave very similar estimates of life expectancy. 4. There was also no significant difference between estimates obtained from the Cévennes and the Garrigues, despite their distinct vegetation and climates. Therefore, large regional differences in sandfly population size and the prevalence of canine leishmaniasis cannot be explained by a difference in adult survival rate. 5. With no systematic annual or regional variation, a useful mean life expectancy can be calculated from the data collected at all sites in both years. It is 1.54 (SE 0.04) ovarian cycles. However, this estimate is sensitive to the assumption that survival rate is a discrete rather than a continuous variable. 6. Local variation in the parous rate may be associated with the proximity of traps to P.ariasi emergence sites.