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.     

Canine leishmaniasis: epidemiological risk and the experimental model

Increasing risk factors are making zoonotic visceral leishmaniasis a growing public health concern in many countries. Domestic dogs constitute the main reservoir of Leishmania infantum and Leishmania chagasi, and play a key role in the transmission to humans. New reagents and tools allow the detailed investigation of canine leishmaniasis, permitting the monitoring of the immunological status of dogs in both natural and experimental infections. Such studies are essential to determine the basis of the canine protective immune response and to establish a laboratory model, a significant aspect for the development of vaccines against canine leishmaniasis.     

Canine leishmaniasis in the Rif mountains (Moroccan Mediterranean coast): a seroepidemiological survey

A sero-epidemiological survey has been conducted in several localities of the province of Nador to investigate canine leishmaniasis in the North-Eastern slope of the Rif mountains (Mediterranean coast of Morocco). Serum samples collected from 257 dogs were analysed using indirect fluorescent antibody test (IFAT) and enzyme-linked immunosorbent assay (ELISA) to detect anti-Leishmania infantum antibodies. Forty eight (18.7%) of the screened dogs were IFAT positive and 54 (21.0%) were ELISA positive; the concordance of the two methods was 96.1%. The prevalence of infection is significantly higher in dogs more than four years of age whereas no significant difference in prevalence of infection was seen between males and females. The frequent symptoms observed in seropositive dogs were the enlargement of lymph nodes (57.4%), emaciation (51.9%) and skin involvement (25.9%). However, 38.9% of those dogs showed no one of the major symptoms of visceral leishmaniasis. Leishmania isolated from three of the examined dogs was identified as L. infantum MON-1. These results show that the North-Eastern slope of the Rif mountains is one of the most active Mediterranean areas of visceral leishmaniasis and confirm that the dog is the main reservoir of L. infantum.     

Interleukin-12 augments a Th1-type immune response manifested as lymphocyte proliferation and interferon gamma production in Leishmania infantum-infected dogs

The dog is the major reservoir for human visceral leishmaniasis caused by Leishmania infantum. Interleukin-12 is considered to have an essential role in the development of both innate and adaptive immunity to Leishmania spp. and other intracellular pathogens. This study focused on the influence of IL-12 in experimental and natural canine visceral leishmaniasis. Responses of peripheral blood mononuclear cells to IL-12, interleukin-10 and Leishmania soluble antigen were evaluated in L. infantum experimentally infected oligosymptomatic beagles, uninfected beagles, naturally infected polysymptomatic dogs, and their matched uninfected controls. Leishmania soluble antigen induced strong peripheral blood mononuclear cells proliferation both in experimentally infected dogs (median stimulation index [SI]=15.01), and in naturally infected dogs (SI=8.86), but not by cells from the control groups. IL-12 addition further enhanced cell proliferation in naturally (SI=14.95), but not in experimentally infected animals. Peripheral blood mononuclear cells from experimentally infected dogs were able to produce significant amounts of IFN-gamma (3.39 ng/ml) upon LSA stimulation, but no such production was detected in cells from naturally infected or control animals. Interestingly, addition of IL-12 reversed the inhibitory effect of LSA on IFN-gamma production by cells from polysymptomatic naturally infected dogs and the uninfected beagles (4.84 and 7.45 ng/ml, respectively), and further increased IFN-gamma production by peripheral blood mononuclear cells from experimentally infected oligosymptomatic dogs (29.28 ng/ml). IFN-gamma mRNA expression correlated well with IFN-gamma production. Addition of IL-10 to Leishmania soluble antigen stimulated peripheral blood mononuclear cells inhibited proliferation and IFN-gamma production in experimentally infected dogs. Thus, the ability of IL-12 to augment IFN-gamma production by peripheral blood mononuclear cells from dogs with experimental or natural symptomatic canine visceral leishmaniasis makes it a good candidate for cytokine therapy in dogs that are refractory to current therapy.     

Susceptibility to visceral leishmaniasis in the domestic dog is associated with MHC class II polymorphism

Zoonotic visceral leishmaniasis (VL) is a disease of dogs, humans and other animals caused by the intracellular macrophage parasite Leishmania infantum. We examined the relationship between DLA class II alleles ( DRB1, DQA1, DQB1) and the course of infection in a cohort of Brazilian mongrel dogs exposed to natural L. infantum infection. DLA alleles were typed by sequence-based typing. DLA-DRB1 genotype was significantly associated with levels of anti- Leishmania IgG and parasite status assessed by PCR. Dogs with DLA-DRB1*01502 had higher levels of specific IgG and an increased risk of being parasite positive compared with dogs without this allele, controlling for other alleles and significant variables. No significant associations were seen for DLA-DQA1 or DLA-DQB1 alleles. These results suggest that the DLA-DRB1 locus plays a role in determining susceptibility to canine VL. As the domestic dog is the main reservoir for human infection, the identification of genetic factors influencing canine resistance or susceptibility to VL may provide insights into the immunology and potential control through vaccination of VL.     

Visceral leishmaniasis in eastern Sudan: parasite identification in humans and dogs; host-parasite relationships

In 1996, an epidemic outbreak of visceral leishmaniasis (VL) started in Barbar el Fugara, a village in Gedarif State (eastern Sudan). From 1997 to 2000, regular epidemiological studies were carried out in the human population, as well as in mammals and sand flies. In symptomatic patients, 46/69 lymph node, 6/20 post kala-azar dermal leishmaniasis (PKDL) and 1/4 cutaneous cultures in NNN medium were positive. In 69 dogs, 23/79 lymph node cultures were positive. In other mammals (47 rodents, five donkeys, one mongoose and one monkey) spleen and/or blood cultures were negative. Characterization of isolated strains (by starch gel electrophoresis and isoelectrofocusing) identified three zymodemes of Leishmania donovani, two of L. infantum and two of L. archibaldi complexes from patient samples and three zymodemes of L. donovani, three of L. infantum and two of L. archibaldi complexes from dog samples. Five of them were present in both man and dog. For the first time, a strain from a PKDL case was identified as L. infantum, and a child had the same L. infantum zymodeme in VL and in subsequent PKDL. Blood samples from dogs were studied by immunofluorescent antibody test (IFAT). The seroprevalence in dogs was 72.5%, 74.3% and 42.9% in 1998, 1999 and 2000, respectively. By using CDC miniature light traps 12 745 sand flies were collected and then identified. Phlebotomus papatasi (7%) and P. orientalis (5%) were sympatric, mainly inside homes (85% and 75%, respectively). These results, the relative stability of seroprevalence in dogs and the intradomiciliar presence of P. orientalis, known as a vector of VL in Sudan, suggest several hypotheses: (i) man is responsible for the disease in dogs, (ii) the dog is the reservoir of VL, (iii) the dog is an intermediate host between a possible sylvatic cycle and the anthroponotic cycle. More extensive studies are needed to assess the transmission cycle of VL in this area of Sudan.     

Leishmania infantum infection rates in Phlebotomus perniciosus fed on naturally infected dogs under antimonial treatment

Dogs naturally infected with Leishmania infantum Nicolle were treated with three courses of meglumine antimoniate. Changes were observed in the dogs' clinical signs, antibody titres and in infection rates of Phlebotomus perniciosus Newstead fed on the dogs. A large reduction in the sandfly infection rate was observed for 4-5 months after the first treatment. The use of antimonial drugs is advocated for the control of canine leishmaniasis and to reduce risks of L.infantum transmission.     

Canine leishmaniasis in Campania: new and old foci

Canine Leishmaniasis (CanL) is endemic in Campania Region (Italy) and is strictly related to Human Visceral Leishmaniasis. Past and present reports of the prevalence in the Region show that exist places were CanL has been known for a century (Vesuvius and Ischia Foci) and other localities where the disease appears to be recent (Caserta and Salerno provinces); moreover, the zoonosis is seen not only in endemic foci (autochthonous), but also in non-endemic areas (imported cases), for example in the Benevento and Avellino provinces. Two zymodemes have been identified in human and canine population and also in sandflies: MON 1 and MON 72. Endemic or stable CanL foci correspond with Vesuvius Area, Ischia island, Maddaloni and neighbouring Commons, other foci in the Salerno province. These foci are associated with optimal ecological condition, abundance of reservoirs and hosts, abundance of phlebotomine vectors, prevalence in canine population around 10-40%, incidence in canine population 5%, risk for human population 0.002%. Instable foci occur at the border of the stable foci: they may be the result of changes in climate with the occasional introduction of infected dogs in the areas; in the foci are registered low presence of phlebotomine vectors, prevalence around 0.5-3%, sporadic human cases. Today, in Campania region CanL undoubtedly has an increased incidence and a wider geographic distribution than before: new cases are now reported in areas that were previously non-endemic. Ecological, demographic and environmental changes, large population movements, urbanization have led to an increased incidence and to importation into suburbs with high densities of people and sand-flies. These changes include "global warming", increased number of stray dogs, dogs and population movements, changes in human population (increased number of immune-depressed and old people). Nowadays, the most important focus of CanL and Human Visceral Leishmaniasis of the Mediterranean area is located in Campania Region: during the year 2000, 143 cases of Human Visceral Leishmaniasis have been recorded in Italy, an half of them (83 cases) in Campania region.     

The current status of zoonotic leishmaniases and approaches to disease control

Leishmaniases are a complex of world-wide diseases with a range of clinical and epidemiological features caused by Leishmania spp. of protozoan parasites. Among 15 well-recognised Leishmania species known to infect humans, 13 have zoonotic nature, which include agents of visceral, cutaneous and mucocutaneous forms of the disease in both the Old and New Worlds. Currently, leishmaniases show a wider geographic distribution and increased global incidence of human disease than previously known. Environmental, demographic and human behavioural factors contribute to the changing landscape of leishmaniasis, which includes increasing risk factors for zoonotic cutaneous leishmaniases and new scenarios associated with the zoonotic visceral leishmaniases. The latter consist of the northward spread of Leishmania infantum transmission in Europe and America, the identification of unusual mammal hosts, and the decline of HIV-Leishmania co-infections in southern Europe following the introduction of the highly active antiretroviral therapy. Few advances have been made in the surveillance and control of the zoonotic leishmaniasis, however a number of tools have been developed for the control of the canine reservoir of L. infantum. These include: (i) several canine vaccine candidates, in particular an FML Leishmania enriched fraction showing good clinical protection, has been registered in Brazil for veterinary use; (ii) a number of insecticide-based preparations have been specifically registered for dog protection against sand fly bites. Laboratory and field studies have shown improved efficacy of these preparations for both individual and mass protection.     

Emergence of Zoonotic Canine Leishmaniasis in the United States: Isolation and Immunohistochemical Detection of Leishmania infantum from Foxhounds from Virginia.

ABSTRACT. Previously considered an exotic disease, canine leishmaniasis caused by Leishmania infantum has recently been detected within the foxhound population in the United States and parts of Canada. Leishmania infantum is the etiologic agent of visceral leishmaniasis in many areas of the world and dogs are considered a major reservoir host for human Leishmania infections. Human visceral leishmaniasis has recently emerged as an opportunistic infection among individuals co-infected with HIV/AIDS and in persons taking immunosuppressive drugs. We report the isolation of L. infantum from 3 naturally infected foxhounds from Virginia by culture of popliteal lymph node and bone marrow, and the development of an immunohistochemical test to detect the parasite in tissues.     

Leishmaniasis in central and southern Tunisia: current geographical distribution of zymodemes

The authors report the identification of Leishmania strains isolated from the Centre and the South of Tunisia. 266 strains were isolated between 1998 and 2006 from human (n=221 strains) and dogs (n=45 strains) hosts. The isoenzymatic identification exhibits the presence of in total five zymodemes belonging to three Leishmanio complexes: Leishmania infantum, L. major and L. killicki. All strains isolated from human and canine visceral leishmaniasis belonged to L. infantum. zymodeme MON-1 was the only one isolated from canine visceral leishmaniasis. However, it is predominant in human visceral leishmaniasis beside zymodeme MON-24 which was detected in two provinces of the Centre (Monastir and Kairouan) and zymodeme MON-80 isolated for the first time in Kairouan province. Three complexes are responsible for human cutaneous leishmaniasis: L. major MON-25 is the parasite the most frequently found in its classic foci in the Centre and the South of the country. L. infantum MON-24 was isolated for the first time in a small locality of Sfax (southern Tunisia) showing the appearance of a new focus of L. infantum. L. killicki was isolated in its original focus of Tataouine and in two new foci of the central part of the country (Sidi Bouzid and Kairouan).     

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.     

Variability of Leishmania (Leishmania) infantum among stocks from immunocompromised, immunocompetent patients and dogs in Spain

Abstract Leishmania (Leishmania) infantum is the causative agent of both the cutaneous and visceral forms of leishmaniasis in southwest Europe; the dog is the main reservoir. In order to identify the L. (L.) infantum zymodemes present in Spain, a total number of 85 Leishmania stocks isolated from dogs (31), HIV-positive patients (46) with visceral or cutaneous leishmaniasis, a patient with visceral leishmaniasis complicating renal transplantation (1) and immunocompetent patients (7) with visceral or cutaneous leishmaniasis, have been characterized by isoenzyme typing. All canine stocks were MON-1, which is the most widespread zymodeme in the Mediterranean area. In immunocompetent patients three zymodemes were found: MON-1 (2), MON-24 (2) and MON-34 (3). Nine different zymodemes were obtained in stocks from HTV co-infected patients, indicating a higher variability of L. (L.) infantum amongst them: MON-1 (in 21 stocks), MON-24 (7), MON-28 (1), MON-29 (3), MON-33 (7), MON-34 (1) and MON-183 (4). Two new zymodemes, MON-198 (1) and MON-199 (1), were described among HIV patients from Spain. The stock from the renal transplanted patient was MON-1. The exclusive presence of certain zymodemes in immunocompromised patients and their absence in typical cases of cutaneous and visceral     

Evaluation of two DNA probes specific for Leishmania infantum in the diagnosis of canine leishmaniasis

This study reports on the evaluation of two L. infantum specific DNA probes for the diagnosis of canine leishmaniasis. The probes presented very satisfying performances in terms of specificity (100%) and predictive value of the positive result (100%). However, their sensitivity (35.3%) and the clinical complexity of canine infections render their use difficult in epidemiological surveys of visceral leishmaniasis aiming at measuring the prevalence of the dog infection by L. infantum. The sensitivity of these tools has improved (66.7%) when dogs presenting patent leishmaniasis were considered. Such probes constitute appropriate tools to confirm suspected cases of leishmaniasis. Unlike the classical parasitological and serological tools, this kind of tools allows a concomitant detection and identification of the causative agent. Therefore, despite their low sensitivity, these probes can still be of importance in epidemiological investigations.     

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.     

Prevention and control of leishmaniasis vectors: current approaches

Phlebotomine sandflies (Diptera: Psychodidae) are the suspected or proven vectors of Leishmania spp. in at least 88 countries, including over 40 Phlebotomus species in the Old World and a further 30 belonging to the genus Lutzomyia in the New World. In recent years, both cutaneous (CL) and zoonotic visceral leishmaniasis (ZVL) have become increasingly prevalent in urban areas, including large Latin American cities. A similar trend has been recorded in all Mediterranean areas during the last decade. Based on mathematical models, insecticidal control of sandflies appears to represent a more effective way of reducing Leishmania infantum transmission than the present strategy of culling infected dogs in Latin America as well as being more acceptable to the human population. Since man is a dead-end host of most Leishmania species, treatment of existing human cases generally does not affect transmission. Interruption of the cycle by vector control may offer a cheaper, more practical solution to treatment and improved knowledge of the alternatives available could lead to preventative measures being undertaken in more leishmaniasis foci. In this note a review of current knowledge on sandfly control is presented. Different measures to control phlebotomine sandflies, including residual spraying of dwellings and animal shelters, insecticide treated nets, application of repellents/insecticides to skin or to fabrics and impregnated dog collars are discussed. Although effective in urban areas with high concentrations of sandflies, residual spraying of insecticides is no often longer tenable in most situations. In rural areas where dwellings are more dispersed and surrounded by large, untargeted "reservoir" populations of sandflies, residual spraying of houses may be both impractical for logistic reasons and ineffective. Actually, this control measure depends on the availability of a suitable public health infrastructure, including adequate supplies of insecticide, spraying equipment and trained personnel. Ideally such personnel should be trained in insecticide application, monitoring techniques and interpretation of sampling data, as well as safety techniques. To date reports of resistance refer to one insecticide (DDT) in only three species (Phlebotomus papatasi, P. argentipes and Sergentomyia shorti) in one country (India), although there are reports of increased tolerance to this compound in several countries. Fortunately the insects remain susceptible to all the major insecticidal groups. Impregnated bednets may offer the best solution in rural areas where transmission is largely intradomiciliary. This measure has the advantage that it can be employed at the individual household level and affords collateral benefits such as privacy and control of other biting insects such as mosquitoes, fleas and bedbugs. Sandfly larvae are generally difficult to find in nature so control measures that act specifically against immatures are not feasible, although the effectiveness of a few biological and chemical agents has been demonstrated in laboratory evaluations. In ZVL foci, where dogs are the unique domestic reservoir, a reduction in Leishmania transmission would be expected if we could combine an effective mass treatment of infected dogs with a protection of both healthy and infected dogs from the sandfly bites. Laboratory and field evaluations have shown that impregnated dog collars and topical application of insecticides could protect dogs from most sandfly bites by means of both anti-feeding and killing effect of the pirethorids used.     

Are insecticide-impregnated dog collars a feasible alternative to dog culling as a strategy for controlling canine visceral leishmaniasis in Brazil?

In a zoonotic visceral leishmaniasis (ZVL)-endemic area in Brazil, deltamethrin-impregnated collars (DMC) were fitted to 136 dogs for 5 months and significantly reduced the odds of increasing their anti-Leishmania antibody titer during this period by 50% (95% confidence interval 29-87%, P=0.01), as compared with a population of 97 uncollared dogs with pre-intervention prevalence within the same town. Mathematical modeling suggests that under typical Brazilian ZVL-endemic conditions, the epidemiological impact of community-wide DMC application should be greater than the currently practiced dog culling strategy, but that its impact will be dependent on collar coverage and loss rate. Both interventions should have a higher proportional impact in regions of lower endemicity, but the relative advantage of DMC over culling increases with transmission rate. Sensitivity analyses indicate that the impact of either intervention is not significantly affected by variation in the biology of the sandfly vector, but is greatly influenced by variation in dog mortality and serorecovery rates.     

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 long term experimental study of canine visceral leishmaniasis

Previous studies on Leishmania infantum and the canine immune response are derived mainly from short-term studies. To date, there have been no longitudinal studies that perform a serial analysis of the intensity of infection in conjunction with immunological parameters and clinical signs in Leishmania-infected dogs. For this purpose, six dogs were infected experimentally by the i.v. route and were monitored for 1 year. Clinical, immunological (humoral and cellular response) and parasitological (parasitaemia) parameters were evaluated monthly. Four dogs developed clinico-pathological signs compatible with leishmaniasis, whereas two dogs showed few abnormalities during the study. Evaluation of clinical, immunological and parasitological parameters showed that the intensity of Leishmania infection in blood samples, as indicated by the amount of Leishmania DNA, was correlated significantly with IgG, IgG1, IgG2, IgA, and IgM concentrations and with clinical signs. Parasitaemia and Leishmania-specific cell-mediated immunity were inversely correlated. Moreover, higher quantities of Leishmania DNA were detected in the liver, spleen, lymph node, skin and bone marrow of dogs exhibiting clinical signs than those exhibiting few such signs. These findings suggest that progressive disease in experimental canine leishmaniasis is associated with specific T-cell unresponsiveness and unprotective humoral responses which allow the dissemination and multiplication of L. infantum in different tissues.     

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.