Evidence for an impact on the incidence of canine leishmaniasis by the mass use of deltamethrin-impregnated dog collars in southern Italy

Dogs are the domestic reservoir of Leishmania infantum Nicolle (Kinetoplastida: Trypanosomatidae), the agent of zoonotic human visceral leishmaniasis. In southern Europe, where canine leishmaniasis (CanL) is widespread due to L. infantum, killing seropositive dogs is considered unacceptable and drug treatment has low efficacy in preventing transmission. We made a field evaluation of the efficacy of deltamethrin dog collars in a CanL focus of southern Italy, Mount Vesuvius area of Campania region, where the vector is Phlebotomus perniciosus Newstead (Diptera: Psychodidae), by assessing their impact on the incidence of CanL in an intervention town, compared to that in dogs of control towns where no collars were fitted. During two consecutive transmission seasons, collars were fitted to 350 (1998) and 354 (1999) dogs from San Sebastiano al Vesuvio (70% of the canine population). Control dogs (371 and 264 in the 2 years, respectively) were from four towns of the same area. Before each transmission season, the CanL seroprevalence in the intervention and control towns was evaluated by cross-sectional surveys and found to be similar (about 15% in 1998 and 10% in 1999, respectively). After each transmission period, incidence rates of seroconversions were determined in adult dogs that were serologically negative before the season under evaluation, and in puppies. After the 1998 season, 2.7% of the dogs in the intervention town seroconverted compared to 5.4% in the control towns (50% protection, P = 0.15). After the 1999 season, 3.5% of collared dogs seroconverted compared to 25.8% of control dogs (86% protection, P < 0.001). The increase in seroconversion rates recorded in control dogs suggests an increase in the Leishmania force of infection in the canine reservoir during the 1999 sandfly season, as supported by the concomitant increase of human cases in control towns and in the whole Campania region. Our results suggest that the impact of mass use of deltamethrin-impregnated dog collars on the incidence of CanL may be negligible during low transmission seasons, or probably in low endemic foci, but can be very strong when the force of transmission is high.     

A survey for American cutaneous and visceral leishmaniasis among 1,342 dogs from areas in Rio de Janeiro (Brazil) where the human diseases occur

There are areas in the periphery of Rio de Janeiro city where human cases of Visceral and/or Cutaneous Leishmaniasis occur. The parasites have been identified as Leishmania donovani and Leishmania braziliensis braziliensis respectively. A survey for Leishmaniasis was done among 1,342 dogs from those areas using an indirect immunofluorescent test. From the dogs, 616 came from areas where only human cases of Visceral Leishmaniasis occurred, 373 from an area where all human cases were of Cutaneous Leishmaniasis and 353 from a third area (Campo Grande) where both visceral and cutaneous human cases were detected. The prevalence of parasite antibody titers among dogs from areas of Cutaneous Leishmaniasis was significantly higher than that of Visceral Leishmaniasis (8.6% vs. 4.3%, p less than 0.02). The highest prevalence was observed among dogs from the area where both diseases are present (12.7%).     

A stable focus of canine leishmaniosis in the Bologna Province, Italy

During an epidemiological survey carried out for two consecutive years (2001-2002), autochthonous cases of canine leishmaniosis (CanL) were reported in Communes of the Bologna Province (Emilia-Romagna Region, northern Italy), involved in the past (1971-1972) in a severe outbreak of human visceral leishmaniosis (VL). Serological controls, carried out by immunofluorescence antibody test on a sample of owned dogs, detected a mean prevalence of 2.5% in the first year in 4 Communes, and of 11.2% in the second year in only one Commune, where an incidence value of 9.3% was assessed. The autochthonous origin of the infection was confirmed in 11 out of 13 positive animals in the first year and in 5 out of 6 new cases in the second year. In one case the parasitological examinations led to the isolation of leishmaniae characterized as Leishmania infantum zymodeme MON 1. Entomological surveys carried out during two sandfly seasons in one of the areas concerned by the VL outbreak showed the presence of Phlebotomus perfiliewi and, to a lesser extent, of P perniciosus, both proven vectors of L. infantum in Italy. The results obtained seem to suggest the presence of a stable focus of CanL in the territory involved in the previous VL outbreak of 1971-1972, within which the infection in the canine population had been assessed only serologically. Such an epidemiological situation may be seen either as the persistence of an old focus or as a new imported one.     

Monitoring of canine leishmaniasis in northern Italy: an update from a scientific network

Canine leishmaniasis (CanL) due to Leishmania infantum is a disease of great veterinary importance and a serious public health problem. In humans, L. infantum causes visceral (VL) and cutaneous leishmaniasis (CL) and the distribution of VL overlaps that of CanL. Currently, VL is considered by WHO as an emerging zoonosis in southern Europe. The dog is the only domestic reservoir of the infection and phlebotomine sandflies are the only proven vectors of leishmaniasis for dogs and humans. CanL is endemic in Italy, particularly in central and southern regions, including islands. Until 1983, all regions of northern Italy but Liguria and some territories of Emilia Romagna were considered free from CanL. From early '90s new stable foci of CanL have appeared, most of them located within classical endemic areas including territories of Emilia Romagna, Tuscany, Umbria, Marche, and Abruzzi regions. But the most relevant aspect, from an epidemiological point of view, has been the appearance of stable CanL foci in northern Italy, namely in Veneto and Piedmont regions. In these two foci, entomological surveys showed the presence of P. perniciosus and of a second phlebotomine vector, P. neglectus, which may have played a role in the CanL diffusion in some parts of northern Italy. Furthermore, in these areas, autochthonous human VL cases have occurred. There is therefore a realistic risk that CanL infection could rapidly spread through northern latitudes and a surveillance activity is strongly needed. For this reason, in October 2002, thanks to the collaboration and support of Intervet Italia, the network "LeishMap" was created, with the main purpose of monitoring the spread of CanL and vectors in northern Italy. LeishMap consists of scientific and sanitary institutions with proven experience both in field surveys and diagnostic methodologies on CanL and phlebotomine vector. It is organised in 4 Operational Units (OU), represented by researchers of the Veterinary Faculties of the University of Bologna, Padua, Milan and Turin, under the scientific coordination of the MIPI Department, ISS of Rome and with the collaboration of private and public veterinarians operating in the regions under study. During the first year of activity, each OU was involved in the serological and entomological surveillance of several territories in the respective regions, where recent autochthonous CanL cases were registered. The studies have involved five regions, namely Valle D'Aosta, Piedmont, Lombardia, Veneto, Trentino-Alto Adige and Emilia Romagna. In the Symposium 6 of this Congress we report detailed results of a retrospective analysis of data concerning CanL and vectors in northern Italy till 2002 and the preliminary results of 2003 on the seroprevalence rates observed in foci studied and on the entomological surveys carried out. In summary, the results outlined that already known foci of CanL are expanding from the original sites. Several new foci have been identified and many others are at high risk of evolving toward a stable endemicity. P. perniciosus has been found in all but one the suspected new foci. In Emilia Romagna region P. perfiliewi was identified in 2 areas and in one was the only species present. The occurrence of P. neglectus was confirmed in three regions, Veneto, Lombardia and Piedmont. In conclusion, from the 2002-2003 LeishMap activities it appears that further monitoring activities are necessary to identify new endemic foci of CanL, this representing the prerequisite for the implementation of programs for leishmaniasis control in northern Italy.     

Leishmania infection and host-blood feeding preferences of phlebotomine sandflies and canine leishmaniasis in an endemic European area,the Algarve Region in Portugal

The Algarve Region (AR) in southern Portugal, which is an international tourist destination, has been considered an endemic region of zoonotic leishmaniasis caused by Leishmania infantum since the 1980s. In the present study, phlebotomine and canine surveys were conducted to identify sandfly blood meal sources and to update the occurrence of Leishmania infection in vectors and dogs. Four sandfly species were captured: Phlebotomus perniciosus, Phlebotomus ariasi, Phlebotomus sergenti and Sergentomyia minuta. In one P. perniciosus female, L. infantum DNA was detected. Blood meal tests showed that this species had no host preferences and was an opportunistic feeder. An overall canine leishmaniasis (CanL) seroprevalence of 16.06% was found; the seroprevalence was 3.88% in dogs housed in kennels and 40.63% in dogs that attended veterinary clinics. The simultaneous occurrence of dogs and P. perniciosus infected with L. infantum in the AR indicates that the region continues to be an endemic area for CanL. Our results reinforce the need for the systematic spatial distribution of phlebotomine populations and their Leishmania infection rates and the need to simultaneously perform pathogen monitoring in both invertebrate and vertebrate hosts to investigate the transmission, distribution and spreading of Leishmania infection.     

A new stable focus of canine leishmaniasis in northern Italy

A new stable focus of canine leishmaniasis (CanL) was identified in a coastal Adriatic area of the Emilia-Romagna Region in Northern Italy. Following the first clinical cases observed starting from 1998, a seroepidemiological survey was carried out on owned dogs from two communes and on animals housed in dog pounds of the Rimini province. Sixteen out of 612 dogs (2.6%) resulted positive to the IFA test. The 16 positive dogs all came from the two communes, with seroprevalences of 3 and 6%, respectively. The autochthonous origin of the infection was confirmed in all the cases. The parasitological investigation led to the isolation and identification of the parasite as Leishmania infantum Zymodeme MON 1. An entomological survey showed that Phlebotomus perniciosus and P. perfiliewi are present in this area and that P. perfiliewi was very abundant in one collection site. The risk of the establishment of a permanent transmission of the infection in the area, previously considered CanL-free, must be analysed in view of further investigations to be extended also to neighbouring areas.     

Infantile visceral leishmaniasis in the Campania region, Italy: experience from a Paediatric Referral Centre

In the first half of the 20th century, visceral leishmaniasis (VL) was a common infantile syndrome in coastal territories of the Campania region of Italy. After World War II, the incidence dropped to a few cases/year for three decades; in late 1980s the disease reemerged among both children and adults. To face the VL recrudescence, a Paediatric Reference Centre was established at the Santobono-Pausilipon hospital in Naples, for the clinical diagnosis, care and drug treatment of all infantile VL cases occurred in the Campania region. Rapid laboratory diagnosis was secured by a Diagnostic Reference Centre established at the Istituto Superiore di Sanità. Here, we report on the epidemiological and parasitological features of all cases referred to the Centre in the past 15 years. From 1990 to March 2004, a total of 255 cases were diagnosed and treated at the Centre. The Figure shows the yearly trend of patients (min. 3 cases in 1990 and 1991, max. 30 cases in 2000). There were 135 males (52.9%); the age ranged 4 months-14 years, but 189 patients (74.1%) were < or = 3 years old. The majority of the patients (189, 74.1%) were from the Naples province, with a cluster of 102 cases (40% of total patients) from the towns and districts surrounding Vesuvius. Twenty-seven cases (10.6%) were from the town of Maddaloni, Caserta province, whereas 15 cases (5.9%) were from coastal villages of the Salerno province. Only 1 and 2 cases were from Benevento and Avellino provinces, respectively. All patients but seven, who have been treated with antimonial drugs in the 1990-1993 period, were successfully treated with a liposomal amphotericin B regimen. From bone-marrow aspirate samples, 138 Leishmania cultures were obtained in EMTM and Sloppy Evans' media, of which 134 have been typed by the electrophoretic analysis of 13 isoenzymes. Two zymodemes (Z) of L. infantum were routinely identified over the study period, ZMON-1 (the commonest zymodeme in the Mediterranean area) and ZMON-72, variant from MON-1 in PGM mobility and detected only in our region. The latter, identified in 61 patients (45.5%), was found exclusively distributed in towns of the Vesuvius area and in Maddaloni until 1996, but in recent years it appears to have spread to other areas of the Naples (including the island of Ischia) and Caserta provinces, but not to Salerno province. In conclusion, the VL macrofocus of the Naples-Caserta area is probably responsible for the highest number of infantile cases among any VL macrofoci described in southern Europe. Considering the limited efforts paid to control the canine reservoir, rapid diagnosis and appropriate treatment of patients still remain the first-line control measures aimed at reducing the health impact of the disease.     

Canine leishmaniosis in Tunisia: Growing prevalence,larger zones of infection

BackgroundDiscovered by Nicolle and Comte in 1908 in Tunisia, Leishmania infantum is an intracellular protozoan responsible for zoonotic canine leishmaniosis (CanL) and zoonotic human visceral leishmaniasis (HVL). It is endemic in several regions of the world, including Tunisia, with dogs considered as the main domestic reservoir. The geographic expansion of canine leishmaniosis (CanL) has been linked to global environmental changes that have affected the density and the distribution of its sand fly vectors.Methodology/Principal findingsIn this study, a cross-sectional epidemiological survey on CanL was carried out in 8 localities in 8 bioclimatic areas of Tunisia. Blood samples were taken from 317 dogs after clinical examination. Collected sera were tested by indirect fluorescent antibody test (IFAT; 1:80) for the presence of anti-Leishmania infantum antibodies. The overall seroprevalence was 58.3% (185/317). Among positive dogs, only 16.7% showed clinical signs suggestive of leishmaniosis. Seroprevalence rates varied from 6.8% to 84.6% and from 28% to 66% by bioclimatic zone and age group, respectively. Serological positivity was not statistically associated with gender. The presence of Leishmania DNA in blood, using PCR, revealed 21.2% (64/302) prevalence in dogs, which varied by bioclimatic zone (7.3% to 31%) and age group (7% to 25%). The entomological survey carried out in the studied localities showed 16 species of the two genera (Phlebotomus and Sergentomyia). P. perniciosus, P. papatasi, and P. perfiliewi were the most dominant species with relative abundances of 34.7%, 25% and 20.4%, respectively.Conclusions/SignificanceThe present report suggests a significant increase of CanL in all bioclimatic areas in Tunisia and confirms the ongoing spread of the infection of dogs to the country’s arid zone. Such an expansion of infection in dog population could be attributed to ecological, agronomic, social and climatic factors that affect the presence and density of the phlebotomine vectors.     

Estimation of Canine Leishmania Infection Prevalence in Six Cities of the Algerian Littoral Zone Using a Bayesian Approach

A large-scale study on canine Leishmania infection (CanL) was conducted in six localities along a west-east transect in the Algerian littoral zone (Tlemcen, Mostaganem, Tipaza, Boumerdes, Bejaia, Jijel) and covering two sampling periods. In total 2,184 dogs were tested with an indirect fluorescent antibody test (IFAT) and a direct agglutination test (DAT). Combined multiple-testing and several statistical methods were compared to estimate the CanL true prevalence and tests characteristics (sensitivity and specificity). The Bayesian full model showed the best fit and yielded prevalence estimates between 11% (Mostaganem, first period) and 38% (Bejaia, second period). Sensitivity of IFAT varied (in function of locality) between 86% and 88% while its specificity varied between 65% and 87%. DAT was less sensitive than IFAT but showed a higher specificity (between 80% and 95% in function of locality or/and season). A general increasing trend of the CanL prevalence was noted from west to east. A concordance between the present results and the incidence of human cases of visceral leishmaniasis was observed, where also a maximum was recorded for Bejaia. The results of the present study highlight the dangers when using IFAT as a gold standard.     

Epidemiology of Visceral Leishmaniasis in Georgia

This study investigated the transmission and prevalence of Leishmania parasite infection of humans in two foci of Visceral Leishmaniasis (VL) in Georgia, the well known focus in Tbilisi in the East, and in Kutaisi, a new focus in the West of the country. The seroprevalence of canine leishmaniasis was investigated in order to understand the zoonotic transmission. Blood samples of 1575 dogs (stray and pet) and 77 wild canids were tested for VL by Kalazar Detect rK39 rapid diagnostic tests. Three districts were investigated in Tbilisi and one in Kutaisi. The highest proportions of seropositive pet dogs were present in District #2 (28.1%, 82/292) and District #1 (26.9%, 24/89) in Tbilisi, compared to 17.3% (26/150) of pet dogs in Kutaisi. The percentage of seropositive stray dogs was also twice as high in Tbilisi (16.1%, n = 670) than in Kutaisi (8%, n = 50); only 2/58 wild animals screened were seropositive (2. 6%). A total of 873 Phlebotomine sand flies were collected, with 5 different species identified in Tbilisi and 3 species in Kutaisi; 2.3% of the females were positive for Leishmania parasites. The Leishmanin Skin Test (LST) was performed on 981 human subjects in VL foci in urban areas in Tbilisi and Kutaisi. A particularly high prevalence of LST positives was observed in Tbilisi District #1 (22.2%, 37.5% and 19.5% for ages 5–9, 15–24 and 25–59, respectively); lower prevalence was observed in Kutaisi (0%, 3.2% and 5.2%, respectively; P<0.05). This study shows that Tbilisi is an active focus for leishmaniasis and that the infection prevalence is very high in dogs and in humans. Although exposure is as yet not as high in Kutaisi, this is a new VL focus. The overall situation in the country is alarming and new control measures are urgently needed.     

Canine leishmaniasis: evolution of the chemotherapeutic protocols

Dogs are the domestic reservoir for Leishmania infantum (syn.: L. chagasi), the parasite causing zoonotic visceral leishmaniasis (ZVL) in both the Old and New Worlds. In foci of canine leishmaniasis (CanL), symptomatic disease occurs in less than 50% of infected dogs, and is characterized by chronic evolution of viscero-cutaneous signs. Among strategies recommended to control ZVL, detection and drug treatment of infected dogs are usually employed in the endemic countries of southern Europe. However, the conventional antileishmanial drugs successfully used in human therapy, such as pentavalent antimonials, amphotericin B, pentamidine or miltefosine, have low efficacy in the treatment of CanL. In dogs, these drugs induce only temporary remission of clinical signs, do not prevent occurrence of relapses, and often cause severe side effects. Leishmaniotic dogs may be classified into 4 groups: 1) Asymptomatic resistant dogs ("contacted dogs"), 2) Asymptomatic dogs (preclinical), 3) Dogs with minimal signs of leishmaniasis (oligosymptomatic dogs? Chronic form of leishmaniasis?), 4) Dogs suffering from different forms of clinical leishmaniasis (symptomatic dogs). The dog's immunological status and the associated clinical signs may influence the efficacy of antileishmanial drugs. Subjects belonging to groups 2, 3 and 4 should be always treated, in order to reduce their parasite load. Parameters that must be considered before starting the antileishmanial treatment are hemogram, renal and hepatic functions, electrophoretic protein pattern, antileishmania antibody titres, and bone marrow and lymph node parasite load. The most common antileishmanial drugs currently used in Italy to treat CanL are pentavalent antimonials (meglumine antimoniate) and allopurinol, alone or in combination. Other used drugs are aminosidine (syn.: paromomycin), pentamidine, metronidazole and spyramicin. Each drug regimen has different duration, from a few weeks (aminosidine), to a few months (meglumine antimoniate) or several months (allopurinol). One of the most recent drug used in human VL is liposomal amphotericin B (AmBisome--L-AMB), a powerful antileishmanial drug in both experimental murine models and in VL patients. In Italy, L-AMB is now considered the drug of choice for the treatment of human cases. However, in HIV co-infected patients high doses of L-AMB are ineffective in obtaining a radical cure. In dogs, L-AMB treatment rapidly leads to clinical recovery but is uneffective to eliminate the parasites. Drugs containing amphotericin B should not be used in veterinary practice in order to avoid selection of parasites resistant to the drug, as it already occurred for the pentavalent antimonials. Currently, there is not a standard protocol for CanL treatment in Italy, as there is an extreme variability of proposed dosages. Clinical studies on immunotherapeutics and new antileishmanial drugs, such as miltefosine and its derivates, are in progress.     

KDNA Genetic Signatures Obtained by LSSP-PCR Analysis of Leishmania (Leishmania) infantum Isolated from the New and the Old World

Background

Visceral Leishmaniasis (VL) caused by species from the Leishmania donovani complex is the most severe form of the disease, lethal if untreated. VL caused by Leishmania infantum is a zoonosis with an increasing number of human cases and millions of dogs infected in the Old and the New World. In this study, L. infantum (syn. L.chagasi) strains were isolated from human and canine VL cases. The strains were obtained from endemic areas from Brazil and Portugal and their genetic polymorphism was ascertained using the LSSP-PCR (Low-Stringency Single Specific Primer PCR) technique for analyzing the kinetoplastid DNA (kDNA) minicircles hypervariable region.

Principal Findings

KDNA genetic signatures obtained by minicircle LSSP-PCR analysis of forty L. infantum strains allowed the grouping of strains in several clades. Furthermore, LSSP-PCR profiles of L. infantum subpopulations were closely related to the host origin (human or canine). To our knowledge this is the first study which used this technique to compare genetic polymorphisms among strains of L. infantum originated from both the Old and the New World.

Conclusions

LSSP-PCR profiles obtained by analysis of L. infantum kDNA hypervariable region of parasites isolated from human cases and infected dogs from Brazil and Portugal exhibited a genetic correlation among isolates originated from the same reservoir, human or canine. However, no association has been detected among the kDNA signatures and the geographical origin of L. infantum strains.     

Potential of Artesunate in the treatment of visceral leishmaniasis in dogs naturally infected by Leishmania infantum: Efficacy evidence from a randomized field trial

Leishmaniasis is among the world’s most neglected diseases. Dogs are the main reservoirs/hosts of Leishmania infantum, causative agent of both canine and human visceral leishmaniosis. Canine leishmaniasis (CanL) represents a public health problem as one of the most prevalent zoonotic diseases worldwide. Current therapeutics present drawbacks; thus, there is a need for more effective, safer, and cheaper drugs. The aim of this study was to evaluate and to compare the efficacy of oral administration of artesunate or meglumine antimoniate/allopurinol in dogs with clinical leishmaniasis. Forty-two dogs with naturally occurring clinical leishmaniasis were included in this open-label, simple randomized positive-control clinical field trial with 6 months of follow-up. Dogs received meglumine antimoniate 100 mg/kg/day and allopurinol 30 mg/kg/day for 28 days (control group, n = 26) or artesunate 25 mg/kg/day for 6 days (test group, n = 16). The animals were evaluated for their clinical evolution, parasite load (by qPCR) and humoral response at different time points: 0, 30, 90, and 180 days after treatment. Data analyses showed a significant improvement in both groups in clinical scores, parasitemia and antibody titers after treatment. Compared to the control group, the artesunate group showed significantly lower clinical score (P = 0.0001), lower parasitemia (P = 0.0001) and antibody titers after 6 months of follow-up. Compared to baseline values, a rapid, significant reduction (P < 0.012) in antibody levels, 2.28- versus 3.04-fold for the control versus artesunate groups, respectively, was observed 30 days after treatment. Antibody levels continued to decrease further in the artesunate group, where 58% of cases became seronegative at the 6-month follow-up. All qPCR-positive dogs were negative after treatment with artesunate, while 14.3% remained positive with the appearance of two new cases in the control group. Artesunate was well tolerated, and no side effects were recorded. Treatment failures were similar in both groups with 27.27% (6/22), including 18.18% (4/22) mortality in the control group, versus 26.66% (4/15), including 13.33% (2/15) mortality in the artesunate group. This is the first report showing the potential of artesunate in the treatment of dogs with clinical leishmaniasis. Artesunate showed higher efficacy than the current first-line treatment for CanL without any adverse effects. It could be a good alternative chemotherapy for CanL, and may be considered for further studies in human leishmaniases. Further clinical trials are needed to confirm these findings, to determine if there are relapses after treatment and if dogs remain infective to sandflies, to define the ideal therapeutic dosage and duration of treatment with artesunate.     

Heterogeneity of environments associated with transmission of visceral leishmaniasis in South-eastern france and implication for control strategies

Background

Visceral leishmaniasis due to Leishmania infantum is currently spreading into new foci across Europe. Leishmania infantum transmission in the Old World was reported to be strongly associated with a few specific environments. Environmental changes due to global warming or human activity were therefore incriminated in the spread of the disease. However, comprehensive studies were lacking to reliably identify all the environments at risk and thereby optimize monitoring and control strategy.

Methodology/Findings

We exhaustively collected 328 cases of autochthonous visceral leishmaniasis from 1993 to 2009 in South-Eastern France. Leishmaniasis incidence decreased from 31 yearly cases between 1993 and 1997 to 12 yearly cases between 2005 and 2009 mostly because Leishmania/HIV coinfection were less frequent. No spread of human visceral leishmaniasis was observed in the studied region. Two major foci were identified, associated with opposite environments: whereas one involved semi-rural hillside environments partly made of mixed forests, the other involved urban and peri-urban areas in and around the region main town, Marseille. The two neighboring foci were related to differing environments despite similar vectors (P. perniciosus), canine reservoir, parasite (L. infantum zymodeme MON-1), and human host.

Conclusions/Significance

This unprecedented collection of cases highlighted the occurrence of protracted urban transmission of L. infantum in France, a worrisome finding as the disease is currently spreading in other areas around the Mediterranean. These results complete previous studies about more widespread canine leishmaniasis or human asymptomatic carriage. This first application of systematic geostatistical methods to European human visceral leishmaniasis demonstrated an unsuspected heterogeneity of environments associated with the transmission of the disease. These findings modify the current view of leishmaniasis epidemiology. They notably stress the need for locally defined control strategies and extensive monitoring including in urban environments.     

Interpretation of laboratory data during cryptic leishmaniasis in dog

Leishmaniasis is a zoonosis caused by an intracellular parasite belonging to the genus Leishmania. In Europe, Africa, South America and China, visceral leishmaniasis is caused by L. infantum. The vectors of leishmaniasis are phlebotomine sandflies belonging to the genera Phlebotomus. According to the World Health Organization there are 2 million new cases each year and 1/10 of the world's population is at risk of infection. Leishmaniasis is considered a zoonosis and human are generally accidental hosts. The animal reservoir includes rodents, dog and other mammals. Several studies have indicate that half of the dogs with antileishmanial antibodies have no signs of disease although, animal with subclinical infections are potentially infectious to sand flies. The factors determining susceptibility or resistence to visceral leishmaniasis remain unclear, but the genetics of the host may play a major role. Clinical signs are: intermittent fever, hepatosplenomegaly, skin lesions and ulcers, alopecia, onychogryphosis, anemia, thrombocytopenia and hypergammaglobulinemia. In mice, the outcome of infection depends on the polarized activation of one of two subsets of CD4+ T cells, Th1 or Th2, the subdivision into Th1 and Th2 cells is based on the pattern of cytokines that they produce. Th1 cells produce gamma interferon (IFN-gamma) and interleukin -2 (IL-2), whereas Th2 cells produce IL-4, IL-5, and IL-10. An important difference between susceptible and resistant mice is that the resistant mice are able to switch to a Th1 profile and control the disease. An important factor in the "decision" to form a Th1 or Th2 phenotype is the early cytokine environment, and IL-12 is one of the cytokines that contributes significantly to the establishment of the Th1 phenotype. Canine leishmaniosis is endemic in the Mediterranean basin and, in most cases is caused by the parasite Leishmania infantum. The main clinical findings are skin lesions, local or generalized lymphoadenopathy, loss of body weight, glomerulopathy, ocular lesions, epistaxis and lameness. Non pruritic skin lesions are the usual manifestation and several forms have been described, such as exfoliative dermatitis and alopecia, and ulcerative, nodular and pustular dermatitis. Seroepidemiological studies of canine leishmaniasis have revealed a large number of asymptomatic seropositive animals. Moreover in areas where leishmaniasis is highly endemic, high proportion of apparently healthy animals show low levels of anti-Leishmania antibodies. Others have regressive forms of the desease, and their antibody levels will decrease in the following months or years; still others maintain low levels of antibodies without developing the desease for many years. However, the total number of infected animals is unknown. Canine leishmaniasis is a major zoonosic parasitic disease, enzootic in the Mediterranean area, caused by the intracellular protozoan Leishmania infantum. The dog is the main reservoir host of the parasite. However, most infected dogs do not present any clinical signs, and there is evidence that Leishmania infection prevalence rates in areas of endemicity are higher than those ascertained by serological studies. Visceral leishmaniasis is becoming a real problem of public health because it is an opportunistic infection in immunocompromised patients and in human immunodeficiency virus-positive subjects. The detection of the extent of the infection, particularly among asymptomatic dogs, is of great importance for the control of leishmaniasis. PCR has been applied successfully in recent years to detect Leishmania spp. even in the cases with any of the clinical manifestation of leishmaniasis. Very recently, real-time PCR for Leishmania has been applied to evaluate the parasitic load of dog tissues both at the time of the diagnosis and during follow-up of the therapy and to measure cytokine mRNA levels in different clinical samples of infected and uninfected dogs.     

Canine leishmaniosis - new concepts and insights on an expanding zoonosis: part one

Recent research has provided new insights on the epidemiology, pathology and immunology of canine leishmaniosis (CanL) and its genetic basis. The prevalence of infection in endemic areas is considerably higher than that of apparent clinical illness. In addition, infection spreads rapidly among dogs in the presence of optimal conditions for transmission. Infection involves a variety of granulomatous and harmful immune-mediated responses, and susceptibility to the disease is influenced by a complex genetic basis. These concepts will be instrumental for devising control programs. This review, the first in a series of two articles on CanL, presents an updated view on progress in elucidating the epidemiology and pathogenesis of this challenging disease, and the second part focuses on advances in diagnosis, treatment and prevention.     

Study of an outbreak of cutaneous leishmaniasis in Venezuela. The role of domestic animals

During an outbreak of cutaneous leishmaniasis in a locality (Las Rosas, Cojedes State, Venezuela) previously non-endemic, 12.9% of humans, 7% of dogs and 21.4% of donkeys (Equus asinus) had lesions with parasites. The agent in the three hosts was identified as Leishmania braziliensis, subspecies braziliensis at least in man and donkey. The probable vector was Lutzomyia panamensis. No infection was found in a small sample of wild mammals examined. The outbreak was apparently linked with the importation of donkeys with ulcers, from endemic areas. The authors call attention to the fact that not only in the foci of "uta", but also in areas of the other forms of American cutaneous leishmaniasis, dogs are frequently found infected. They emphasize the necessity of searching for the infection in donkeys and of performing hemocultures and xenodiagnosis with sandflies in human, canine and equine cases, to verify their possible role as sources of infection, and not merely as dead ends in the epidemiological chain of the disease.     

Phlebotomine sand flies (Diptera: Psychodidae) in the municipality of Várzea Grande: an area of transmission of visceral leishmaniasis in the state of Mato Grosso, Brazil

Visceral leishmaniasis (VL) has been naturally transmitted in periurban areas due to the emergence and reemergence of its vectors in such areas. Aimed to further knowledge on ecological aspects affecting the occurrence of phlebotomine sand flies in VL transmission areas in the municipality of Várzea Grande, state of Mato Grosso (MT), Brazil, sand fly captures were carried out. Monthly collections of sand flies were undertaken with CDC light-traps, which were left in both intradomiciliary and peridomiciliary areas of ten residences during four consecutive days between January 2004 and June 2006. Twenty-two species of genus Lutzomyia and one of Brumptomyia were captured. The most abundant species was Lutzomyia longipalpis (65.23%), followed by L. evandroi (16.26%), L. lenti (7.69%), L. whitmani (4.92%), L. sallesi (2.34%) and L. termitophila (1.32%). The highest density of the main VL vector, L. longipalpis, was found in peridomiciliary areas, mostly males. No significant correlation was found between environment (temperature, air relative humidity and rain fall) and phlebotomine density; although a slight increase in sand fly density has been observed in the period following rainfalls, particularly L. longipalpis. No correlation was observed between distribution and density of L. longipalpis, prevalence of human VL cases and the presence of serologically positive dogs. The presence of infected dogs, increased vector density, susceptibility rate and interruption of epidemiological surveillance may raise the risk of VL transmission to man in Várzea Grande.     

Focus: Zoonotic Disease: Eco-epidemiological Aspects of Visceral Leishmaniasis in the Municipality of Diamantina,Jequitinhonha Valley (Minas Gerais State, Brazil)

Background: The present study was carried out in the rural and urban area of Diamantina/Minas Gerais (MG), an endemic municipality for visceral leishmaniasis (VL) in Brazil. Methods: Patient notification records, canine prevalence, and phlebotomine fauna were evaluated. Results: In the period from 2016 to 2018, eight human cases were confirmed, with three deaths, predominantly in males. In the same period, a total of 1,388 dogs resided in the rural and urban area of the municipality were submitted to the DPP® and ELISA, with a percentage of confirmed canine cases of 29.9% and 29.4%, respectively. The entomological study conducted in the municipality revealed the presence of 10 species of sand flies, with a predominance of Lutzomyia longipalpis (55.75%), mainly in the rural area. Conclusions: Unlike what is happening in urban centers, the results of this study suggest that the VL in Diamantina is in the process of urbanization, given the high percentage of confirmed canine cases and the high density of Lu. longipalpis in the rural area of the municipality. These risk factors warn about the need for continuous surveillance and the need to control actions of VL in this area.     

Roe deer (Capreolus capreolus) are a novel potential reservoir for human visceral leishmaniasis in the Emilia-Romagna region of northeastern Italy

Leishmaniasis is a complex human disease caused by intracellular parasites of the genus Leishmania, predominantly transmitted by the bite of sand flies. In Italy, leishmaniasis is caused exclusively by Leishmania infantum, responsible for the human and canine visceral leishmaniases (HVL and CVL, respectively). Within the Emilia-Romagna region, two different foci are active in the municipalities of Pianoro and Valsamoggia (both in the province of Bologna). Recent molecular studies indicated that L. infantum strains circulating in dogs and humans are different, suggesting that there is an animal reservoir other than dogs for human visceral leishmaniasis in the Emilia-Romagna region. In this work, we analyzed specimens from wild animals collected during hunts or surveillance of regional parks near active foci of human visceral leishmaniasis for L. infantum infection in the province of Bologna. Out of 70 individuals analyzed, 17 (24%) were positive for L. infantum. The infection prevalence in hedgehogs (Erinaceus europaeus), roe deer (Capreolus capreolus), badgers (Meles meles), and bank voles (Myodes glareolus) was 80, 33, 25, and 11%, respectively. To distinguish the two strains of L. infantum we have developed a nested PCR protocol optimized for animal tissues. Our results demonstrated that most (over 90%) of L. infantum infections in roe deer were due to the strain circulating in humans in the Emilia-Romagna region.