Leishmaniosis in cats: ABCD guidelines on prevention and management

Feline leishmaniasis in an animal shelter in northeastern Brazil: Clinical aspects, coinfections, molecular detection, and serological study of a new recombinant protein

Infection and clinical cases of leishmaniasis caused by Leishmania infantum in cats have been increasingly reported in several countries, including Brazil. In this study, we used an enzyme-linked immunosorbent assay (ELISA) and an immunochromatographic test (ICT) based on a recombinant antigen (rKDDR-plus) to detect anti-Leishmania antibodies in cats from an animal shelter in northeastern Brazil. We compared the results with an ELISA using L. infantum crude antigen (ELISA-CA). We also investigated the presence of Leishmania DNA in blood or ocular conjunctival samples as well as the association between Leishmania PCR positivity and serological positivity to feline immunodeficiency virus (FIV), feline leukemia virus (FeLV) and Toxoplasma gondii. Concerning serological assays, a higher positivity was detected using the ICT-rKDDR-plus (7.5%; 7/93) as compared to ELISA-rKDDR-plus (5.4%; 5/93) and ELISA-CA (4.3%; 4/93). Upon PCR testing, 52.7% (49/93) of the ocular conjunctival swabs and 48.3% (44/91) of the blood samples were positive. Together, PCR and serological testing revealed overall positivities of 73.1% (68/93) and 12.9% (12/93), respectively. Among PCR-positive samples, 45.5% (31/68) showed co-infection with FIV, 17.6% (12/68) with FeLV, and 82.3% (56/68) with T. gondii. More than half of the PCR-positive cats showed at least one clinical sign suggestive of leishmaniasis (58.8%; 40/68) and dermatological signs were the most frequent ones (45.5%; 31/68). Both tests employing the recombinant antigen rKDDR-plus (i.e., ICT-rKDDR-plus and ELISA-rKDDR-plus) detected more positive cats than the ELISA-CA but presented low overall accuracy. PCR testing using either blood or ocular conjunctival samples detected much more positive cats than serological tests.

FeliLeish: An Update on Feline Leishmaniosis and Factors Associated with Infection in Different Feline Populations from Italy

Feline leishmaniosis is a worldwide infection caused by the parasite of the genus Leishmania transmitted by sandflies. Based on the complexity of epidemiology and diagnosis of this infection, the role of cats in the epidemiology and clinical impact of disease is still under debate. By using serological and molecular methods, this study aimed to update the epidemiology of the infection in different feline populations from various areas of Italy and to study factors associated with the infection. Of 1490 cats tested, 124 (8.3%, 95% CI 6.9-9.9) were infected, 96 had only specific L. infantum IgG, 18 were only positive for parasite DNA and 10 were both IFAT and qPCR positive. Risk factors for infection were sampling in the winter season (OR = 3.2, 95% CI 2.2-4.8), originating from the Sicily region (OR = 2.0, 95% CI 1.3-3.0), male gender (OR = 1.8, 95% CI 1.1-3.2), outdoor lifestyle (OR = 2.3, 95% CI 0.9-5.6) and seropositivity for FIV antibodies (OR = 2.2, 95% CI 1.2-4.2), while sampling in the spring (OR = 0.5, 95% CI 0.3-0.7) and summer (OR = 0.3, 95% CI 0.1-0.7), and originating from the Lazio region (OR = 0.1, 95% CI 0.05-0.4) were protective factors for infection. In endemic areas, Leishmania infection should be investigated by using both serological and molecular methods and cats should be protected from sandfly bites, particularly if they are FIV infected.

First reported case of leishmaniasis in a cat in Trinidad and Tobago

A 3-year-old, female, domestic shorthair cat, was presented to the Veterinary Teaching Hospital at the School of Veterinary Medicine (SVM), Trinidad and Tobago for a swollen nose, and multiple, variably sized small masses on both ears. The initial diagnostic tests included a CBC, serum biochemistry profile, cytological evaluation of masses on the ear and nose, and FeLV/FIV testing. The CBC and biochemistry results were unremarkable except for a hyperproteinaemia and hyperglobulinemia. Cytology of the nose and ear lesions revealed mixed inflammation and high numbers of intracellular and extracellular organisms consistent with Leishmania amastigotes. The cat was FeLV/FIV negative. Histopathology and Leishmania IFA and PCR analysis were subsequently performed, confirming the Leishmania diagnosis. The PCR, DNA sequencing and phylogenetic tree analyses identified L. amazonensis. This is the first reported case of L. amazonensis infection in a domestic animal in Trinidad with molecular characterization indicating it exists in the region and is likely being transmitted by sandflies.

Leishmaniosis in Greece: The Veterinary Perspective

Leishmaniosis caused by the protozoon Leishmania infantum that is transmitted through the bites of infected phlebotomine sandflies is of major veterinary concern in Greece. The country is endemic with particularly favourable environmental conditions for the spread of this infection. Moreover, Greece remains a popular touristic destination, and the continuous travel of pets raises concern regarding the possible dissemination of infection from endemic to non-endemic areas. Dogs are the main reservoir host, although other animal species, including humans, may also be infected. Canine leishmaniosis manifests as a visceral disease that can result in death if left untreated. Serological and molecular epizootiological studies have confirmed circulation of the parasite in Greek canine and feline populations as well as in other mammals. As a result, constant surveillance and identification of high-risk localities are necessary to establish chemoprophylactic protocols for travelling animals to safeguard animal and public health.

Feline leishmaniosis with focus on ocular manifestation: a case report

BACKGROUND

In Europe, feline leishmaniosis is commonly caused by Leishmania infantum. There is little knowledge regarding pathogenesis, ocular manifestations and long-term follow-ups in cats with leishmaniosis.

FINDINGS

A 6-year-old female, spayed European Shorthair cat was imported from Spain to Germany 2 years prior to its first clinical presentation. The cat showed lethargy, weight loss, ulcerative lesions on the front limbs and high-grade chronic uveitis. The diagnosis of L. infantum infection was based on the cytological finding of amastigotes in skin lesions, positive qPCR of EDTA-blood and positive PCR of a cyto-brush sample from the conjunctiva. Supportive findings included positive serology by IFAT, serum protein capillary electrophoresis with peaks in alpha2- and gamma-globulin sections and marked elevation of SAA. Enucleation had to be performed on day 288 on both eyes because of blindness, glaucoma and high-grade uveitis. Histologically, high numbers of Leishmania spp. amastigotes were found in histiocytes. IFAT and PCR were positive in the aqueous humor in both eyes, respectively. Feline leukemia virus antigen and feline immunodeficiency virus antibody testings were positive. Hematological and biochemical results revealed mild leukocytosis with lymphocytosis, monocytosis and eosinopenia as well as marked elevation of SAA and hyperglobulinemia. The cat was treated with allopurinol, responded well and was still alive at follow-up on day 288 after first presentation. However, enucleation was necessary because of refractory glaucoma and uveitis.  CONCLUSION: For the first time, ocular evidence of Leishmania IgG antibodies was demonstrated in the aqueous humor of both eyes in cats. There is limited knowledge about the pathogenesis, treatment options and outcomes in cats infected with L. infantum. This case report supports the hypothesis that immunosuppression increases the risk of clinical signs of leishmaniasis in cats. Alpha2- and gamma-globulin peaks in serum protein capillary electrophoresis are supportive criteria for the diagnosis of L. infantum infection. SAA is valuable for monitoring. Regarding ophthalmology, uveitis and glaucoma may have a poor prognosis.

A case report of leishmaniosis with primary oral manifestation in a cat

A case of leishmaniosis with primary oral manifestations was reported in a 10-year-old neutered domestic shorthair cat. The primary lesion was a maxillary nodular lesion, painful with spontaneous bleeding associated with advanced periodontal disease, which did not resolve with tooth extraction or periodontal treatment. Biopsy revealed chronic neutrophilic and macrophagic infections and amastigote forms of Leishmania sp and molecular tests were able to identify Leishmania infantum. Oral signs resolved after the initiation of etiologic treatment with allopurinol. Distinguishing oral signs of leishmaniosis from other oral inflammatory diseases is important, especially in endemic areas, and co-infections must be considered with any oral manifestations of this disease.

Clinical Case of Feline Leishmaniosis: Therapeutic Approach and Long-Term Follow-Up

Simple Summary

In the present report, clinical, diagnostic, and therapeutical findings observed in a case of feline leishmaniosis (FeL) along with its long-term follow-up data are reported with the aim to provide more evidence-based data on the treatment of this important zoonotic vector-borne disease of cats. The present study represents one of the few reports of FeL with a 28-month follow-up period. This case underlines the effectiveness of allopurinol and highlights how the interruption of treatment frequently leads to relapse, impairing the animal’s health condition and prognosis.

Abstract

The response to allopurinol treatment and survival time of a case of feline leishmaniosis in a FIV co-infected cat is herein reported. In May 2019, a 13-year-old neutered European Shorthair male was referred due to weight loss and exfoliative dermatitis. Lymphadenomegaly and splenomegaly were detected upon clinical inspection, while the presence of several Leishmania infantum amastigotes were detected on splenic and lymphonodal fine needle aspiration (FNA). Allopurinol (10 mg/kg PO q 12 h) was administered. After two months, the cat’s clinical symptoms disappeared, and the owners decided to interrupt the therapy. In February, two reddish nodular fleshy neoformations appeared in both eyes, and amastigotes of Leishmania were detected by cytology on conjunctival swabs. Allopurinol treatment was re-started at the same rate; the ocular lesions regressed in two weeks, and the owner again decided to interrupt the therapy. In July, the patient had a new relapse, but the owner, tired of continuous relapses, refused further treatment of the disease. The cat’s health condition continued to worsen: in October 2021, the ocular lesions appeared again, and in November the patient died. This case underlines the effectiveness of allopurinol and highlights how interruption of treatment frequently leads to relapse, impairing the animal’s health condition and prognosis.

Review and statistical analysis of clinical management of feline leishmaniosis caused by Leishmania infantum

Background

There is limited information about feline leishmaniosis (FeL) management in clinical practice. Leishmania infantum is the species of Leishmania most frequently reported in both dogs and cats in countries of the Mediterranean region (henceforth ‘Mediterranean countries’), Central and South America, and Iran. This study was conducted to provide veterinary clinicians with an updated overview of evidence-based information on leishmaniosis in cats.

Methods

A review was performed using PubMed, Science Direct, Google Scholar and Web of Science. Case reports of FeL caused by L. infantum were sought for the period 1912 to 1 June 2021.

Results

Sixty-three case reports are included in this review. Fifty-nine out of the 63 cats were from Europe, mostly from Mediterranean countries (88.9%). Most of them were domestic short-haired cats (90%) with a mean age of 7.9 years, and had access to the outdoors (77.3%). Sixty-six percent of the cats had comorbidities, of which feline immunodeficiency virus infection was the most frequent (37.7%). Dermatological lesions (69.8%) was the most frequent clinical sign, and hyperproteinemia (46.3%) the most frequent clinicopathological abnormality. Serology was the most performed diagnostic method (76.2%) and was positive for 93.7% of cats. Medical treatment was applied in 71.4% of cats, and allopurinol was the most used drug (74.4%). Survival time was greater for treated cats (520 days; 71.4% of cats) than non-treated cats (210 days; 25.4%).

Conclusions

The majority of the cats had comorbidities, of which feline immunodeficiency virus was the most frequent. Dermatological lesions were frequently reported, and systemic clinical signs and clinicopathological abnormalities were also common. Serology may be useful for the diagnosis of FeL in clinical practice, and a positive titer of ≥ 1/40 may be a useful cut-off for sick cats. The reported treatments and dosages varied, but there was a good clinical response and longer survival in most of the cats treated with allopurinol monotherapy.

Graphical abstract

Serum protein electrophoretogram profile detected in apparently healthy cats infected with Leishmania infantum - Short communication

The information about the clinical features of Leishmania infantum infection in cats is scarce. In this study, we evaluated the serum protein electrophoresis of samples from 19 infected but apparently healthy cats. To detect L. infantum infection, two serological tests, i.e. western blot (WB) and enzyme-linked immunosorbent assay (ELISA) as well as quantitative polymerase chain reaction (qPCR) on the blood samples were performed. Eventual infection by several selected bacterial and viral pathogens was also tested. All but one of the cats were found positive with WB. The WB-negative cat was positive by ELISA only. From the 18 WB-positive cats, only three were positive also by ELISA and eight with qPCR, including the only animal which was positive in all the three tests. No concomitant infections were detected in any of the cats. The main alteration of the proteinogram was characterised by an increase of the α-2 fraction. In the five cats with hypergammaglobulinaemia, the pattern detected was polyclonal. None of the cats were seropositive to any other pathogens tested. The presence of polyclonal gammopathy and elevation of the α-2 fraction could suggest the presence of active infection. In contrast, the only detection of an increase of the α-2 fraction alone with the presence of positive serological result could be associated by immune response activation against L. infantum.

Drug-Dosing Adjustment in Dogs and Cats with Chronic Kidney Disease

Chronic kidney disease is a common kidney disorder in adult and aged dogs and cats; the management of associated complications and comorbidities generally requires a life-long medical treatment to ensure a good quality of life of affected patients. However, indications and the literature on drug dosing in dogs and cats with chronic kidney disease are often lacking. The aim of this review is to revise the current literature on drug dosing in canine and feline patients with renal impairment, with a special focus on the most commonly used medications to manage chronic kidney disease and possible comorbidities.

Nutritional Modulation of the Immune Response Mediated by Nucleotides in Canine Leishmaniosis

Leishmaniasis is an emerging, uncontrolled, and neglected zoonotic disease. Climate change is contributing to its ongoing global expansion. The dog is the main reservoir; hence the importance of implementing effective treatment, prevention, and control measures in this animal species to protect public health. However, although the standard treatment for canine leishmaniosis (CanL) is effective, it does not provide full parasitological clearance, and side effects and drug resistance have been described. The host's immune system plays a key role in the establishment and evolution of leishmaniasis. Dietary nucleotides modulate the immune response and, given their reported efficacy and safety in sick and clinically healthy Leishmania-infected dogs and because they represent a sustainable option with no associated side effects or resistance, they could be included within the prevention, treatment, and control strategies for leishmaniasis. This article briefly summarizes the scientific literature on CanL management, including unresolved issues, and reviews the scientific evidence on immunomodulatory effects of dietary nucleotides in different animal species. It also proposes a CanL management algorithm, including nucleotides. It is concluded that nutritional modulation of the immune response with nucleotides can contribute to better management of leishmaniasis following a One Health approach, especially in the COVID-19 era.

Epidemiological and diagnostic aspects of feline leishmaniasis with emphasis on Brazil: a narrative review

The leishmaniases are a group of diseases caused by the protozoan parasite belonging to the genus Leishmania. In the New World, although dogs are considered the main parasite reservoir, in the last two decades, several studies have confirmed the role of cats (Felis catus) in the epidemiology of the disease and feline leishmaniasis (FeL) is now considered to be an emerging disease. The present review summarizes the current knowledge about FeL, focusing on important immunopathological aspects, epidemiology, and diagnostic methods applied for felines in Brazil. Cats are infected with the same species of Leishmania found in dogs (i.e., Leishmania infantum). Like dogs, skin lesions are the most common in cats with clinical FeL, mainly affecting the cephalic region and less frequently the legs which may be accompanied by generalized signs or visceral involvement. Information on the immune response of cats to Leishmania infection is scarce; however, efficient infection control is seen in most cases. For diagnosis, generally, the same methods as those in dogs are used, mainly serological tools. But there is a lack of studies focusing the performance of these methods for diagnosing FeL. The estimated overall prevalence of FeL in Brazil is 8%, with L. infantum being the most prevalent species. However, infections with Leishmania braziliensis and Leishmania amazonensis have also been reported. In conclusion, although there has been an increase in the publication related to FeL in Brazil in recent years, there is a lack of research relating immune response and diagnosis of these animals. Cats have been shown to be competent hosts for Leishmania parasites, and their role in the epidemiology of the disease cannot be underestimated, especially in areas of Brazil where the disease is historically endemic.

Feline Leishmaniosis in Northwestern Italy: Current Status and Zoonotic Implications

Leishmaniasis remains one of the major neglected tropical diseases. The epidemiological profile of the disease comprises a wide range of hosts, including dogs and cats. Despite several studies about feline Leishmaniosis, the role of cats in disease epidemiology and its clinical impact is still debated. The present study raises awareness about the impact of leishmaniasis in cats from an endemic region in of Northwestern Italy (Liguria). A total number of 250 serum and 282 blood samples were collected from cats, then assessed for Leishmania infantum (L. infantum) serologically using western blot (WB) and molecularly using polymerase chain reaction (PCR). We also tested the association of Leishmania infection with some infectious agents like haemotropic Mycoplasma, Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV) together with the hematobiochemical status of the examined animals. Interestingly, all tested animals were asymptomatic and out of 250 examined serum samples, 33 (13.20%) samples (confidence interval (CI) 95% 9.56-17.96%) were positive at WB for L. infantum, whereas of the 282 blood samples, 80 (28.36%) returned a positive PCR (CI 95% 23.43-33.89%). Furthermore, there was a statistical association between PCR positivity for L. infantum and some hematological parameters besides FIV infection as well as a direct significant correlation between Mycoplasma infection and WB positivity. Taken together, the present findings report high prevalence of L. infantum among cats, which reinforces the significance of such positive asymptomatic animals and confirms the very low humoral response in this species. In addition, the laboratory values provide evidence that infection by the parasite is linked to alteration of some hematological parameters and is correlated to some infectious agents. These data are of interest and suggest future research for accurate diagnosis of such zoonosis.

Feline Leishmaniasis Caused by Leishmania infantum: Parasite Sequencing, Seropositivity, and Clinical Characterization in an Endemic Area From Brazil

Zoonotic leishmaniasis caused by Leishmania infantum is a disease of One Health concern since human and animal cases and environmental damage are interconnected. L. infantum has a complex epidemiological cycle with multiple hosts, including mammals-humans, domestic, and wild animals-and arthropod vectors. Knowledge on mammal infections in endemic areas is crucial for developing control strategies. This work aimed to detect and characterize L. infantum infection in domestic cats from areas where human and canine leishmaniasis cases occur. No cases of feline leishmaniasis (FeL) had been previously reported in those areas. Five municipalities from Bahia state were chosen, comprising 2,480.8 km² with 1,103,866 inhabitants. Ninety domiciliated and/or sheltered cats underwent clinical examination and serology by a rapid reference test recommended by the Brazilian government. Cytology, PCR, and parasite DNA sequencing were performed in bone marrow samples. Rapid tests detected antibodies in 5.6% (5/90) of the cats. Leishmania infantum infection was confirmed in 7.8% (7/90) of the cats by PCR, sequencing, and parasite isolation. Three out of the five municipalities (60%) had infected cats, and PCR positivity varied from 6.9 to 29%. One cat was categorized as harboring active L. infantum infection with amastigote forms in bone marrow smears. No clinical signs were detected at the first clinical exam, but 1 month later the cat developed severe FeL. The cat isolate was grown in culture, typed and its DNA sequence was homologous to the L. infantum reference strain (PP75). In conclusion, cats are potential hosts and may acquire L. infantum in endemic areas where canine and human cases occur. For cats, the need for surveillance, differential diagnosis and clinical care is highly recommended since a fast clinical progression of FeL developed in a subclinical animal. An accurate standardized immunodiagnostic assay for FeL is warranted.

Feline Leishmaniosis: An Emerging Public Health Problem

Leishmaniosis is the third most important vector-borne disease in humans, preceded by malaria and lymphatic filariasis, and it is considered endemic in tropical and subtropical areas, where higher temperatures favor development of its vector, sandflies. This zoonotic disease is caused by infection of protozoa Leishmania spp. and the most serious mucocutaneous and visceral form is produced by Leishmania infantum, which predominates in the Mediterranean region. The usual hosts for this parasite are dogs and humans, but an increment in cases of L. infantum infection has been observed in cats in the last years. This increase could be due to the use of sandflies repellents in dogs, obligating the parasite to looking for other hosts. The role of cats in the epidemiology of this disease is unknown, although increase of prevalence of feline leishmaniosis has been observed in endemic areas in the last years. Diagnostic techniques and treatments in cats are not standardized, which makes it difficult to establish prevalence and epidemiology of feline leishmaniosis. Furthermore, the clinical signs and immune response against Leishmania in cats are different to those in dogs, with an observed increment of drug resistance. It is necessary to increase our knowledge about L. infantum infection in cats, including clinical signs, transmission, treatments, and the role of cats in the increasing of zoonoses. Finally, new alternative treatments are required for controlling the spread of this disease in all species of mammals.

Xenodiagnosis in four domestic cats naturally infected by Leishmania infantum

Leishmaniasis is a neglected tropical disease that continues to pose a serious public health problem. Albeit dogs have long been held as the major reservoirs of Leishmania infantum, the involvement of domestic cats in the zoonotic cycle of visceral leishmaniasis has gained prominence. Here, 240 cats were evaluated by clinical signs and haematological/biochemical changes compatible with leishmaniasis and were diagnosed by serological, molecular, and parasitological techniques. Thus, four cats naturally infected by L. infantum were submitted to xenodiagnosis. A total of 203 females of Lutzomyia longipalpis were subjected to feeding on four cats, with all females completing the blood meal. Parasitological and molecular assays were carried out to evaluate the presence of L. infantum in the sand flies' midgut. Promastigotes were observed in 10 females (6.5%) that fed on one cat, and L. infantum DNA was detected in 17 (8.4%) females that fed on two cats. Our results strengthen the evidence that naturally infected cats are capable of transmitting L. infantum to sand flies.

Serum amyloid A levels and alpha 2 and gamma globulins on serum protein electrophoresis in cats exposed to and infected with Leishmania infantum

Background

Dogs are the main reservoir hosts of Leishmania infantum; nevertheless, recent investigations indicate a likely role for cats in the epidemiology of Leishmania infection. Feline leishmaniosis (FeL) remains poorly characterised, partly due to the lack of suitable diagnostic tools. This study aimed to compare serum amyloid A (SAA) levels and serum protein electrophoresis (SPE) profiles (specifically, alpha 2 and gamma globulins) in cats naturally exposed to or infected by L. infantum from southern Italy versus those of healthy controls and versus cats with neoplastic or inflammatory conditions from non-endemic areas.

Methods

Serum or plasma samples from four cohorts of cats were analysed for SAA levels and by SPE: (i) G1: healthy controls from Leishmania-non-endemic regions of Switzerland; (ii) G2: cats pre-diagnosed with neoplastic or inflammatory conditions available from the University of Cambridge sample archive; (iii) G3: L. infantum-seropositive, quantitative (q)PCR-negative cats from southern Italy; (iv) G4: L. infantum-seropositive and qPCR-positive cats from southern Italy. SAA data were assessed for normality and homoscedasticity using the Shapiro–Wilk and Levene’s tests, respectively; the Kruskall–Wallis test, followed by Dunn’s test with Bonferroni correction were subsequently used to compare SAA serum levels between groups. A weighted generalised linear model with a binomial distribution was used to assess statistically significant differences in the numbers of animals displaying elevated gamma globulins and increased alpha 2 globulins between groups.

Results

Overall, 68 samples were analysed (G1: n = 16, G2: n = 20, G3: n = 20, G4: n = 12). Cats suffering from neoplastic and inflammatory conditions (G2 ) showed significantly higher SAA levels than healthy controls (G1) (median values [interquartile range]: G1: 0.00 [0.00–0.00] mg/l versus G2: 0.85 [0.00–49.55] mg/l). G2, G3 and G4 cats showed higher percentages of individuals with increased alpha 2 globulins (percentages ± standard error: G1 = 20.0% ± 10.3, G2 = 80.0% ± 8.9, G3 = 70.0% ± 10.2, G4 = 75.0% ± 12.5) and gamma globulins (G1 = 0.0% ± 0, G2 = 65.0% ± 10.7, G3 = 50.0% ± 11.2, G4 = 58.3% ± 14.2) than healthy control cats (G1). For all three markers, no significant difference between cats within G2, G3 and G4 was recorded.

Conclusions

This study indicates that the proportions of animals with elevated levels of alpha 2 and gamma globulins are significantly higher in cats exposed to and infected with L. infantum. Levels of SAA and alpha 2 and gamma globulins may not be used to differentiate between L. infantum infection or exposure, and neoplastic and/or inflammatory conditions.

Graphic Abstract

Skin Lesions in Feline Leishmaniosis: A Systematic Review

Feline leishmaniosis (FeL) is increasingly reported throughout the world and skin lesions predominate in the clinical picture. There are, however, few evidence-based data on cutaneous feline leishmaniosis and directions are strongly needed for a better management of the disease. In this study, we systematically reviewed what is currently known about the clinical dermatological presentation of FeL through analysis of the literature and, further, by adding unpublished cases managed by Italian veterinary dermatologists. Sixty-six feline cases of cutaneous leishmaniosis published in 33 articles between 1990 and 2020 met the inclusion criteria and were analyzed. Six unpublished cases of cutaneous FeL managed by Italian dermatologists were also reviewed. The majority of cases were reported from South America, followed by Europe and North America. Nodules were the most frequently reported clinical signs and the presence of Leishmania in lesioned skin was assessed mainly by cytology. A total of six Leishmania species have been identified as being responsible for skin lesions. Coinfections by FIV or FeLV were reported in 12.1% and 9.1% of the cases, respectively. Clinical data including treatment have been analyzed and discussed to provide directives for proper management of the disease for which cats may also serve as domestic reservoirs for human infections.

Leishmania mexicana in a central Texas cat: clinical presentation, molecular identification, sandfly vector collection and novel management

Case summary

This case report documents the clinical appearance, diagnosis and novel treatment of a central Texas cat with cutaneous leishmaniosis. The cat presented with a linear erosion on the right pinnal margin, an ulcerated exophytic nodule on the right hock and a swelling in the right nostril. Cytological and histopathological findings were consistent with leishmaniosis. PCR confirmed the presence of Leishmania mexicana, a species endemic to Texas. An epidemiological investigation was conducted by trapping sandflies from the cat’s environment. Sandflies collected were identified as Lutzomyia species, known vectors of Leishmania species. Given the lack of validated medical therapies for L mexicana in cats, treatments typically prescribed for canine leishmaniosis were administered. Allopurinol achieved clinical success but was discontinued due to suspected drug-related neutropenia. Topical imiquimod also improved lesional skin but was not sustainable due to application difficulty. Oral administration of artemisinin resulted in significant clinical improvement of cutaneous lesions without reported adverse events. Nearly 8 months after the initiation of artemisinin therapy, the cat remained systemically healthy with stable lesions.

Relevance and novel information

This case report demonstrates endemic feline leishmaniosis in central Texas and provides the clinician with alternative therapeutic options for medical management.

Evaluation of clinicopathological abnormalities in sick cats naturally infected by Leishmania infantum

Feline infection by Leishmania infantum (syn. L. chagasi) has been described in areas where canine leishmaniosis is endemic. A wide variety of clinicopathological abnormalities have been reported in cats presenting clinical signs of leishmaniosis but there is a paucity of information regarding cats infected by L. infantum that do not suffer from leishmaniosis but from other diseases. The aim of this study was to compare: a) the frequency of clinicopathological abnormalities and b) the values of hematology, serum biochemistry and urinalysis parameters, between non-infected sick cats and sick cats that were infected by L. infantum. A total of 50 cats with cutaneous, ocular and/or systemic clinical signs that lived in an endemic area and had been tested for infection by L. infantum using PCR from four different tissues, were included. Based on the results of PCR, 20/50 cats were found to be infected and 30/50 non-infected. The only difference between the two groups of cats was that the concentration of inorganic phosphorus (P = 0.043) was higher in infected cats. This finding may suggest an association between infection by L. infantum and feline kidney disease.

Feline leishmaniosis: diagnosis, treatment and outcome in 16 cats

OBJECTIVES

Leishmaniosis is a vector-borne disease and in European countries is caused by Leishmania infantum. Cats are considered secondary reservoirs of the infection in endemic areas. The objective of this retrospective study is to describe the clinical findings, diagnosis, treatment and outcome of feline leishmaniosis (FeL) in 16 cats in Spain.

METHODS

Medical records of cats diagnosed with leishmaniosis were retrospectively reviewed for cases that met the following inclusion criteria: identification of Leishmania organisms and/or DNA on cytological and/or histological specimens and/or a high anti-Leishmania antibody titre, compatible clinical findings and pathological abnormalities.

RESULTS

Sixteen cats met the inclusion criteria, all of which were living in areas endemic for canine leishmaniosis. Systemic signs were present in 11 cases (68.8%). The most common clinical signs on presentation included cutaneous lesions in 12 cats (75%), ocular disease in six cats (37.5%) and anorexia in six cats (37.5%). A polyclonal gammopathy was noted in 12 cats (85.7%). Non-regenerative anaemia and renal abnormalities were present in six (37.5%) and five patients (31.3%), respectively. In nine cats (56.3%), immunosuppressive conditions/comorbidities were identified. The diagnosis was made in eight of the cats (50%) by cytology, but a combination of diagnostic tests was needed for definitive diagnosis in the remaining patients. Twelve cats (75%) were treated specifically for leishmaniosis. Five of the 12 cats (41.7%) did not improve with treatment. The median survival time in the group of patients treated specifically for leishmaniosis was 17 months. Median survival of patients treated with concomitant diseases was 13 months vs 41 months in those without, although this was not statistically significant (P = 0.557).

CONCLUSIONS AND RELEVANCE

Presentation of FeL appears to be similar to canine leishmaniosis but with some specific features: ulcerative and nodular skin lesions are the predominant cutaneous signs; cats with immunosuppressive conditions or coexisting diseases were more commonly present than typically seen in dogs (mainly feline immunodeficiency virus). A combination of diagnostic tests may be needed for definitive diagnosis.

Feline Leishmania spp. Infection in a Non-Endemic Area of Northern Italy

Simple Summary

Leishmaniosis caused by Leishmania infantum is a parasitic disease of people and animals transmitted by sand fly vectors. Although dogs in south and central Italy are most affected, in recent decades feline leishmaniosis (FeL) has become an emerging disease. This study aimed to update information on the presence of FeL in stray cats in Milan, in northern Italy; to compare these results with previous studies performed in the same area; and to report aspects of Leishmania infection in cats. A total of 117 stray cats were included and 10 (8.6%) had L. infantum infection. The parasite was identified in popliteal lymph nodes in five cats and five had antibodies against L. infantum. Most infected cats were from a specific area of Milan. Increased gammaglobulins were seen in infected cats, which also had antibodies against the pathogens Anaplasma phagocytophilum, Chlamydophila felis, and Toxoplasma gondii. There was a high prevalence of FeL in the surveyed area of northern Italy. Further studies are needed to understand if these infected cats are being imported from other areas, or if there is a real Leishmania focus in Milan. Investigation of the presence of sand fly vectors in Milan would be useful.

Abstract

Feline leishmaniosis (FeL) is an emerging vector-borne feline disease, with increasing numbers of cases reported and studies performed internationally. This study aimed to update the epidemiological status for FeL in stray cats in Milan, northern Italy; compare these results with previous studies in Northern Italy; and report clinicopathologic findings and coinfections in cats infected with Leishmania spp. A total of 117 cats were tested for L. infantum and retrovirus infection, hematological, and biochemical parameters. Demographic and clinical data were collected and FeL affected cats screened for selected coinfections. Overall, 10/117 (8.6%) cats tested positive for L. infantum: in five cats L. infantum DNA was found in popliteal lymph nodes and five were IFAT seropositive at titers from 1:80 to 1:160. Infected cats were concentrated in a specific area of Milan (p = 0.0154). No specific clinicopathologic abnormalities or retroviral infections were significantly linked to the infection, other than hypergammaglobulinemia (p = 0.0127). Seroreactivity to Anaplasma phagocytophilum, Chlamydophila felis, and Toxoplasma gondii was found in some infected cats. A high prevalence of FeL was found in a non-endemic area of northern Italy and future studies should continually monitor this data to understand whether these cases are imported or if Leishmania vectors are present in this area.

First report on natural infection with Leishmania infantum in a domestic ferret (Mustela putorius furo) in Spain

A pet domestic ferret (Mustela putorius furo) with a papular lesion involving the right pinna was diagnosed with chronic pyogranulomatous dermatitis by histopathologic examination. Intralesional, intracytoplasmic oval microorganisms compatible with Leishmania spp. or Histoplasma spp. were observed in macrophages and multinucleate giant cells. Leishmania infantum (L. infantum) infection was diagnosed by PCR, culture in Novy-MacNeal-Nicolle medium, and immunohistochemistry. Abnormal clinicopathological results included increased alanine transferase, alkaline phosphatase, serum gamma glutamyl transferase and polyclonal gammpathy. Anti-Leishmania antibodies were detected by enzyme-linked immunosorbent assay, immunofluorescence antibody test and western blot using L. infantum antigen. Immunoreactivity against the 16 kDa specific L. infantum antigen fraction was observed by western blot. PCR performed in blood samples obtained from this patient after positive parasite isolation detected L. infantum DNA. To the authors' knowledge, this is the first diagnosis and isolation of L. infantum in a domestic ferret naturally infected in an endemic region (Spain) where canine and feline leishmaniosis is frequently detected. According to these findings, ferrets should be included as potential reservoir hosts of L. infantum. Future investigations should analyze the epidemiological role of ferrets in L. infantum infection including the prevalence of infection.

Diagnosis and epidemiology of Leishmania infantum in domestic cats in an endemic area of the Amazon region, Brazil

Visceral leishmaniasis is a zoonotic disease caused by Leishmania infantum for which dogs are the main reservoir. In South America, presence of this disease is expanding along with increasing dispersion of its principal vector, the sand-fly Lutzomyia longipalpis. Feline leishmaniasis is an emerging disease in domestic cats, but epidemiological studies in endemic areas of the Amazon region of Brazil are scarce and the role of cats as reservoirs of L. infantum has been debated. The aim of this study was to investigate L. infantum infection in cats living in the Amazon biome region, using serological and molecular methods. A total of 105 cats were subjected to clinical examination and blood samples were taken for immunofluorescent-antibody (IFAT) serological evaluation, to determine anti-Leishmania antibody titers. Conventional PCR and Sanger's sequencing targeting L. infantum chitinase and Leishmania species ribosomal internal transcribed spacer (ITS-1) encoding genes were performed on conjunctival swabs from these cats. Seropositivity was detected in 32 animals (30.48%), thus confirming that contact between these cats and the parasite was occurring. PCR followed by amplicon sequencing showed that three samples (2.86%) were positive for a chitinase gene and six (5.71%) were positive for the ITS-1 gene. Parasite-positive diagnoses presented a statistically significant association with free access to the streets (p = 0.0111), cohabitation with dogs affected previously by VL (p = 0.0006) and absence of backyard cleaning and garbage collection (p = 0.00003). These results emphasize that cats should be included in epidemiological surveys of leishmaniasis, especially in endemic areas, if not as the reservoir host (unproven), at least as a "sentinel host" that is useful for revealing situations of endemic circulation of L. infantum. Moreover, in these areas, feline leishmaniasis needs to be considered in the differential diagnosis among domestic cats presenting alopecia, rarefied hair, lacerations and ulcerative dermatitis.

Treatment and long-term follow-up of a cat with leishmaniosis

BACKGROUND

Leishmania infection in cats is being increasingly reported in endemic areas. Nevertheless, only a few clinical cases have been described in cats, and even fewer have provided information on the response to treatment and a proper follow-up. Here we report a case of feline leishmaniosis not associated with any other disease or co-infection and document its response to allopurinol treatment and long-term follow-up data.

RESULTS

A 6-year-old domestic shorthair female cat was referred for nodular blepharitis, mucocutaneous ulcerative lesions of the mouth and lymph node enlargement. The cat was moderately anaemic, hyperglobulinaemic and tested negative for feline leukaemia virus and feline immunodeficiency virus. Fine needle aspirates of nodules and mucocutaneous lesions showed the presence of numerous amastigote forms of Leishmania. Leishmania infection was further confirmed by serology (IFAT test, 1:640) and real-time PCR (RT-PCR) on blood and conjunctival swabs. The cat was treated with allopurinol (20 mg/kg SID), which was clinically effective, although the cat remained Leishmania-positive in serology and RT-PCR on blood and conjunctival swabs. Allopurinol treatment was interrupted after seven months because of the healing of all lesions and lack of compliance by the owner. After two years, the cat relapsed displaying almost the same clinical signs and clinicopathological alterations. On this occasion, the parasite was isolated by culture and identified as belonging to L. infantum. Allopurinol treatment was started again but was interrupted several times because of the itching side effect observed. The cat worsened progressively and died two months after the relapse without any chance to shift the treatment to another molecule (e.g. meglumineantimoniate or miltefosine).

CONCLUSIONS

Out of all documented cases of feline leishmanosis, the present case has the longest follow-up period and it is one of the few in which the parasite was isolated and identified. It further confirms the potential progression of Leishmania infection to disease in cats even in the absence of comorbidities. Veterinarians practicing in endemic areas should be aware of this susceptibility, properly include feline leishmaniosis in the differential diagnosis and propose preventative measures to those cats at risk.

Leishmania infantum-specific IFN-γ production in stimulated blood from cats living in areas where canine leishmaniosis is endemic

Background

Feline leishmaniosis caused by Leishmania infantum is considered a rare disease in endemic areas, whereas subclinical infections are common. Immune response plays a key role in driving the course of L. infantum infection in other host species; however, the feline cell-mediated immune response to L. infantum infection has not yet been investigated. The aim of this study was to determine the cell-mediated immune response specific to L. infantum by means of interferon (IFN)-γ release in whole blood assay from cats living in endemic areas (66 in Sicily and 113 in Catalonia) and to compare with antibody levels to L. infantum [enzyme-linked immunosorbent assay (ELISA) and immunofluorescence antibody test (IFAT)], blood parasite load and retroviral infections.

Results

Most cats (n = 140) were L. infantum antibody negative and only 22% (n = 39) were positive. Only 9 and 2% of tested cats had a feline immunodeficency virus (FIV) infection or a feline leukemia virus (FeLV) infection, respectively. Thirty-two cats out of 179 (18%) produced IFN-γ after stimulation with L. infantum soluble antigen (LSA) while the majority of cats (93%) produced IFN-γ after stimulation with concanavalin A (ConA). Six LSA-IFN-γ-producer cats were seropositive (three to ELISA and five to IFAT) but they were polymerase chain reaction (PCR) negative, while only one cat was antibody- and PCR-positive. Significant positive correlations were found between IFN-γ concentrations after stimulation with LSA and ConA, and between serology and PCR testing. No association was found between FIV status and LSA or ConA-IFN-γ production. Combining PCR, serology and specific IFN-γ concentration results, we found that 36% of cats studied were exposed to L. infantum.

Conclusions

As expected, cats from endemic areas produce IFN-γ after ex vivo blood stimulation with LSA and therefore are able to activate a cell-mediated adaptive immune response against the parasite that is variably associated with antibody or blood PCR positivity. The association of this assay to serological and molecular tests provides a better estimate of cat exposure to L. infantum.

Granulomatous rhinitis secondary to feline leishmaniosis: report of an unusual presentation and therapeutic complications

Case summary

A 12-year-old male neutered domestic shorthair cat underwent rhinoscopy due to inspiratory dyspnoea and stertor. Rhinoscopy showed signs of chronic rhinitis and a multinodular nasopharyngeal mucosa. A marked infiltrate of macrophages that contained intracellular parasitic forms morphologically compatible with Leishmania amastigotes were observed on histopathological examination of nasal and nasopharyngeal biopsies. PCR from nasal tissue was positive for Leishmania infantum DNA, confirming the diagnosis of granulomatous rhinitis secondary to this parasite. Two eyelid nodules were identified 2 weeks later. Fine-needle aspiration revealed Leishmania amastigotes within macrophages and in the background. Allopurinol therapy was started, but 5 days later the cat developed dermatological signs compatible with a cutaneous adverse drug reaction. The drug was discontinued and meglumine antimoniate prescribed. Twenty-five days later, the cat presented with acute kidney injury and meglumine antimoniate was discontinued. Despite clinical improvement after fluid therapy, mild azotaemia persisted. The cat was subsequently treated with nucleotides and active hexose correlated compounds (N-AHCC). Four months later upper respiratory signs were exacerbated. A relapse of granulomatous rhinitis was suspected and miltefosine therapy started. Chronic kidney disease (CKD) worsened during miltefosine treatment, having improved under fluid therapy. Since then, the cat has been treated with N-AHCC and renal diet and at the time of writing shows stable CKD with no recurrence of respiratory signs.

Relevance and novel information

This case describes Leishmania infantum as a cause of granulomatous rhinitis in a cat without cutaneous lesions, reporting the alternative use of N-AHCC and miltefosine when allopurinol seemed to have induced a cutaneous rash and there was acute kidney injury (AKI) after meglumine antimoniate therapy.

Computed tomographic features of destructive granulomatous rhinitis with intracranial extension secondary to leishmaniasis in a cat

A 5-year-old castrated male Domestic Shorthair cat presented for evaluation of chronic history of nasal discharge and nasal stridor. On computed tomography (CT), a destructive ill-defined mass of soft tissue attenuation was occupying the right nasal cavity and extending into the left nasal cavity, nasopharynx, and rostral cranial cavity. Histopathology of the rhinoscopically excised samples consisted with destructive granulomatous rhinitis secondary to Leishmania spp. Chronic granulomatous rhinitis with intracranial and nasopharyneal extension secondary to Leishmania spp. infection should be included as a differential diagnosis for a destructive nasal mass of soft tissue attenuation, especially in endemic regions for leishmaniasis.

Follow-up monitoring in a cat with leishmaniosis and coinfections with Hepatozoon felis and 'Candidatus Mycoplasma haemominutum'

Case summary

A 6-year-old female neutered domestic shorthair cat from Cyprus was presented with multiple ulcerated skin nodules. Cytology and histopathology of the lesions revealed granulomatous dermatitis with intracytoplasmic organisms, consistent with amastigotes of Leishmania species. Biochemistry identified a mild hyperproteinaemia. Blood extraction and PCR detected Leishmania species, Hepatozoon species and ‘Candidatus Mycoplasma haemominutum’ (CMhm) DNA. Subsequent sequencing identified Hepatozoon felis. Additionally, the rRNA internal transcribed spacer 1 locus of Leishmania infantum was partially sequenced and phylogeny showed it to cluster with species derived from dogs in Italy and Uzbekistan, and a human in France. Allopurinol treatment was administered for 6 months. Clinical signs resolved in the second month of treatment with no deterioration 8 months post-treatment cessation. Quantitative PCR and ELISA were used to monitor L infantum blood DNA and antibody levels. The cat had high L infantum DNA levels pretreatment that gradually declined during treatment but increased 8 months post-treatment cessation. Similarly, ELISA revealed high levels of antibodies pretreatment, which gradually declined during treatment and increased slightly 8 months post-treatment cessation. The cat remained PCR positive for CMhm and Hepatozoon species throughout the study. There was no clinical evidence of relapse 24 months post-treatment.

Relevance and novel information

To our knowledge, this is the first clinical report of a cat with leishmaniosis with H felis and CMhm coinfections. The high L infantum DNA levels post-treatment cessation might indicate that although the lesions had resolved, prolonged or an alternative treatment could have been considered.

Vector-borne diseases in cats in Germany

Vector-borne diseases (VBDs) are caused by a wide range of pathogens, which are transmitted by a variety of vectors, such as ticks and fleas. As a result of climate changes, more vector-borne diseases are becoming endemic in Germany, not only in dogs, but also in cats. For some of the pathogens prevalence data still need to be investigated in Germany. However, natural infections with Bartonella, Anaplasma, haemotropic Mycoplasma and Borrelia species have already been described in German cats. Clinical relevance of these pathogens is not fully understood, and it is still unknown, why most infected cats stay asymptomatic and which predisposing factors contribute to the development of clinical signs in cats. Moreover, there is a risk of zoonotic transmission for some of the pathogens, e.  g., for some Bartonella spp. infections that are associated with cat scratch disease in humans. Due to the increasing number of VBDs in cats in Germany, preventive measures, such as the use of acaricides and insecticides, should be performed on a regular base in order to reduce the risk of these infections.

Phlebotomine sand fly-borne pathogens in the Mediterranean Basin: Human leishmaniasis and phlebovirus infections

Pathogens transmitted to humans by phlebotomine sand flies are neglected, as they cause infectious diseases that are not on the priority list of national and international public health systems. However, the infections caused by protozoa of the Leishmania genus and viruses belonging to the Phlebovirus genus (family Phenuiviridae)—the most significant group of viruses transmitted by sand flies—have a relevant role for human pathology. These infections are emerging in the Mediterranean region and will likely spread in forthcoming decades, posing a complex threat to human health. Four species and 2 hybrid strains of Leishmania are pathogenic for humans in the Mediterranean Basin, with an estimated annual incidence of 239,500–393,600 cases of cutaneous leishmaniasis and 1,200–2,000 cases of visceral leishmaniasis. Among the phleboviruses, Toscana virus can cause neuroinvasive infections, while other phleboviruses are responsible for a typical “3-day fever”; the actual incidence of Phlebovirus infections in the Mediterranean area is unknown, although at least 250 million people are exposed. Here, we reviewed the current literature on epidemiology of sand fly–borne infections in the Mediterranean Basin, with a focus on humans. Our analysis indicates the need for increased public health activities directed to determine the disease burden of these infections as well as to improve their surveillance. Among the emerging challenges concerning sand fly–borne pathogens, the relationships between sand fly–borne protozoa and viruses should be considered in future studies, including epidemiological links between Leishmania and phleboviruses as well as the conditional capacity for these pathogens to be involved in interactions that may evolve towards increased virulence.

Molecular characterization of Leishmania infantum in domestic cats in a region of Brazil endemic for human and canine visceral leishmaniasis

Leishmaniasis is a "neglected tropical disease" and serious public health issue in Brazil. While dogs are recognized as particularly important reservoirs, recent reports of domestic cats infected with Leishmania sp. in urban areas suggest their participation in the epidemiological chain of the parasite in endemic areas. The aim of this study was to screen domestic cats for Leishmania sp. infection in an area where human and canine visceral leishmaniasis are endemic, followed by the identification of the species circulating in cats. We collected peripheral blood, lymph-node aspirates and bone marrow from 100 adult animals, both male and female, and analyzed the samples using cytological and molecular (PCR) detection techniques. We detected Leishmania in 6% of animals, which were then analyzed by RFLP-PCR to identify the species. Leishmania infantum (synonym: L. chagasi), a species responsible for visceral leishmaniasis in humans and other animals, was identified from all six samples. Amastigotes were observed in the peripheral blood, bone marrow and lymph-node aspirates in 4 of the 6 PCR-positive animals. The presence of infected cats in endemic areas should not be neglected, because it demonstrates the potential role of these animals in the biological cycle of the pathogen.

Successful treatment of feline leishmaniosis using a combination of allopurinol and N-methyl-glucamine antimoniate

CASE SUMMARY

This work describes the diagnosis and successful treatment of a 2-year-old domestic cat infected with Leishmania species and presenting fever, and ulcerative and nodular skin lesions after being treated for pyodermatitis for 1 year without clinical improvement. After anamnesis the cat was submitted to a complete clinical examination. Blood was collected for determination of haematological and biochemical parameters, detection of feline leukaemia virus (FeLV), feline immunodeficiency virus (FIV), feline coronavirus (FCoV) and Leishmania amastigotes. Fine-needle aspiration puncture from the skin nodules was also performed. After definitive diagnosis the animal was treated and followed up over a 2 year period. The animal tested negative for FIV-specific antibodies, FeLV antigen and feline coronavirus RNA. Leishmania amastigotes in the skin nodules were confirmed by cytology and molecular diagnosis. Treatment was initiated with allopurinol, resulting in a slight clinical improvement. Thus, N-methyl-glucamine antimoniate was added and administered for 30 days, with complete closure of the ulcerative lesions in the hindlimbs requiring a surgical approach. Close monitoring of the patient in the following 24 months indicated that combined therapy was safe and clinical cure was achieved without further relapses or side effects.

RELEVANCE AND NOVEL INFORMATION

Considering the increasing number of feline leishmaniosis cases and the inconsistent results of most therapeutic protocols described in the literature, the use of new approaches, especially in refractory cases, is essential. Although the use of allopurinol and N-methyl-glucamine antimoniate is off-label in cats, in this case the combination treatment was followed by an extensive analytical monitoring, supporting their safety and effectiveness.

Blood transfusion in cats: ABCD guidelines for minimising risks of infectious iatrogenic complications

OVERVIEW

The availability of blood components has increased the number of indications for transfusing cats, and fresh whole blood is readily accessible to clinicians because it can be taken from in-house donor cats or 'volunteer' feline blood donors. A certain amount of risk remains to the recipient cat, as immediate or delayed adverse reactions can occur during or after transfusion, related to immunemediated mechanisms. This article, however, focuses on adverse events caused by infectious agents, which may originate either from contamination of blood following incorrect collection, storage or transfusion, or from transfusion of contaminated blood obtained from an infected donor.

PREVENTION OF BLOOD CONTAMINATION

In cats, blood cannot be collected through a closed system and, therefore, collection of donor blood requires a multi-step manipulation of syringes and other devices. It is crucial that each step of the procedure is performed under the strictest aseptic conditions and that bacterial contamination of blood bags is prevented, as bacterial endotoxins can cause an immediate febrile reaction or even fatal shock in the recipient cat.

PREVENTION OF DISEASE TRANSMISSION

With a view to preventing transmission of blood-borne infectious diseases, the American College of Veterinary Internal Medicine has adopted basic criteria for selecting pathogens to be tested for in donor pets. The worldwide core screening panel for donor cats includes feline leukaemia virus, feline immunodeficiency virus, Bartonella species and feline haemoplasma. The list should be adapted to the local epidemiological situation concerning other vector-borne feline infections. The most practical, rapid and inexpensive measure to reduce transfusion risk is to check the risk profile of donor cats on the basis of a written questionnaire. Blood transfusion can never, however, be considered entirely safe.

Something old, something new: Update of the 2009 and 2013 ABCD guidelines on prevention and management of feline infectious diseases

OVERVIEW

The ABCD has published 34 guidelines in two Special Issues of the Journal of Feline Medicine and Surgery (JFMS): the first in July 2009 (Volume 11, Issue 7, pages 527-620) and the second in July 2013 (Volume 15, Issue 7, pages 528-652). The present article contains updates and new information on 18 of these (17 disease guidelines and one special article 'Prevention of infectious diseases in cat shelters'). For detailed information, readers are referred to the guidelines published in the above-mentioned JFMS Special Issues.

First case of feline leishmaniosis caused by Leishmania infantum genotype E in a cat with a concurrent nasal squamous cell carcinoma

Case summary

This is the first clinical report of feline viscerocutaneous leishmaniosis caused by Leishmania infantum genotype E associated with an invasive squamous cell carcinoma (SCC) in a domestic cat from Portugal. Initially, the cat presented a single cutaneous lesion in the right nostril. A fine-needle aspiration was performed and Leishmania amastigotes were observed without the presence of cells compatible with neoplasia. Systemic treatment with allopurinol was started. One year later, the cat presented a crateriform non-encapsulated and badly delineated mass in the nasal planum, with naso-oral fistulation and nasal destruction. Histologically, the skin mass consisted on an ulcerative plaque-like lesion with a nasal SCC. Leishmania infantum MON-1 parasites were detected by histopathology, culture and PCR of the skin mass, submandibular and popliteal lymph nodes, liver and spleen. Restriction enzyme analysis revealed genotype E, previously identified in humans and dogs living in the same region.

Relevance and novel information

This is, to the best of our knowledge, the first clinical report of feline viscerocutaneous leishmaniosis caused by L infantum genotype E. The detection and isolation of parasites from a cat that are genetically identical to the ones obtained from humans and dogs with visceral leishmaniosis highlights the need to clarify whether cats play a role in the epidemiology of this parasitic zoonosis. From a clinical point of view, this case reinforces the importance of including leishmaniosis in the differential diagnoses of feline pathology, especially in cats with cutaneous lesions.

What do we know about feline leishmaniosis?

According to the World Health Organization (WHO), endemic areas of leishmaniosis have spread and the number of reported cases has increased. Europe is one of the continents with greatest risk of the re-emergence of this zoonosis. The significance of the cat as a reservoir of Leishmania species and not simply an accidental host seems to be gaining ground, mainly because: (i) cats can present increased seropositivity between serological analyses, but the pattern of seropositivity is not consistent between cats; (ii) cats can be infected for some months and thus are available for sandflies; and (iii) cats transmit the Leishmania species agent in a competent form. Furthermore, cats have behavioural characteristics that contribute to infection by Leishmania infantum and, as such, feline leishmaniosis (FeL) has been reported worldwide. When clinical signs of FeL are present, they are non-specific and frequently occur in other feline diseases. If they go undiagnosed, they can contribute to an underestimation of the actual occurrence of the disease in cats. The low seroprevalence titres, along with the commonly asymptomatic infection in cats, can further contribute to the underestimation of FeL occurrence. This work aims to raise awareness about FeL among veterinarians by providing a review of the current status of FeL infection caused by L infantum worldwide, the major clinicopathological features of infection, along with recent developments on FeL diagnosis, treatment and prevention.

LeishVet update and recommendations on feline leishmaniosis

Limited data is available on feline leishmaniosis (FeL) caused by Leishmania infantum worldwide. The LeishVet group presents in this report a review of the current knowledge on FeL, the epidemiological role of the cat in L. infantum infection, clinical manifestations, and recommendations on diagnosis, treatment and monitoring, prognosis and prevention of infection, in order to standardize the management of this disease in cats. The consensus of opinions and recommendations was formulated by combining a comprehensive review of evidence-based studies and case reports, clinical experience and critical consensus discussions. While subclinical feline infections are common in areas endemic for canine leishmaniosis, clinical illness due to L. infantum in cats is rare. The prevalence rates of feline infection with L. infantum in serological or molecular-based surveys range from 0% to more than 60%. Cats are able to infect sand flies and, therefore, they may act as a secondary reservoir, with dogs being the primary natural reservoir. The most common clinical signs and clinicopathological abnormalities compatible with FeL include lymph node enlargement and skin lesions such as ulcerative, exfoliative, crusting or nodular dermatitis (mainly on the head or distal limbs), ocular lesions (mainly uveitis), feline chronic gingivostomatitis syndrome, mucocutaneous ulcerative or nodular lesions, hypergammaglobulinaemia and mild normocytic normochromic anaemia. Clinical illness is frequently associated with impaired immunocompetence, as in case of retroviral coinfections or immunosuppressive therapy. Diagnosis is based on serology, polymerase chain reaction (PCR), cytology, histology, immunohistochemistry (IHC) or culture. If serological testing is negative or low positive in a cat with clinical signs compatible with FeL, the diagnosis of leishmaniosis should not be excluded and additional diagnostic methods (cytology, histology with IHC, PCR, culture) should be employed. The most common treatment used is allopurinol. Meglumine antimoniate has been administered in very few reported cases. Both drugs are administered alone and most cats recover clinically after therapy. Follow-up of treated cats with routine laboratory tests, serology and PCR is essential for prevention of clinical relapses. Specific preventative measures for this infection in cats are currently not available.

The role of wild canids and felids in spreading parasites to dogs and cats in Europe. Part I: Protozoa and tick-borne agents

Over the last few decades, the world has witnessed radical changes in climate, landscape, and ecosystems. These events, together with other factors such as increasing illegal wildlife trade and changing human behaviour towards wildlife, are resulting into thinning boundaries between wild canids and felids and their domestic counterparts. As a consequence, the epidemiology of diseases caused by a number of infectious agents is undergoing profound readjustements, as pathogens adapt to new hosts and environments. Therefore, there is a risk for diseases of wildlife to spread to domestic carnivores and vice versa, and for zoonotic agents to emerge or re-emerge in human populations. Hence, the identification of the hazards arising from the co-habitation of these species is critical in order to plan and develop adequate control strategies against these pathogens. In the first of this two-part article, we review the role that wild canids and felids may play in the transmission of protozoa and arthropod-borne agents to dogs and cats in Europe, and provide an account of how current and future progress in our understanding of the ecology and epidemiology of parasites, as well as of host-parasite interactions, can assist efforts aimed at controlling parasite transmission.

A survey study on gastrointestinal parasites of stray cats in Azarshahr, (East Azerbaijan province, Iran)

Gastrointestinal parasites are among the most common parasitic infections found in stray cats, which might act potential helminthic parasites to domestic cats. The objective of this study was to determine the prevalence of gastrointestinal parasites in stray cats in the city of Azarshahr, which is located in East Azerbaijan province, Iran. A cross-sectional study was conducted on 50 necropsied stray cats, trapped and collected from different geographic regions of Azarshahr. From a total 50 stray cats examined, 15 (30 %) were female and 35 (70 %) were male. Overall 47 cats (94 %) were identified as infected with at least one of the endoparasites. The prevalence of parasites found were: Taenia taeniaeformis (60 %), Dipylidium caninum (58 %), Taenia hydatigera (24 %), Mesocestoides lineatus (78 %), Ancylostoma tubaeforme (14 %), Toxascaris leonina (30 %), Toxocara cati (78 %), Physaloptera praeputialis (10 %), and Syphacia obvelata (10 %). Contamination rate for zoonotic parasites of cat was greater than expected in AzarShahr region. Therefore, appropriate control measures should be taken and preventive methods should be applied.

Persistence of phlebotomine Leishmania vectors in urban sites of Catania (Sicily, Italy)

Background

Pioneering research on “Mediterranean Kala-Azar” carried out by Adler and Theodor early in the past century (~1930s) had identified Catania city (Sicily) as a major focus of the disease nowadays known as zoonotic visceral leishmaniasis (VL). Despite the fact that disease in both humans and dogs has continued to be highly prevalent in the Catania province up to the present times, research on Leishmania vectors in this urban focus dates back to that distant period. This study aimed to evaluate the persistence and current composition of the sand fly fauna in urban environments of Catania in recent years, 2006 and 2013.

Methods

In 2006 fifty-one suitable collecting sites were identified within 44 sub-units of a grid drawn to include the urban Catania area. In 2013 the survey was restricted to four of the most productive and representative sites resulting from the 2006 survey. In both periods 3 collections per month were performed using standard sticky traps set for 3 days in wall holes/cavities along public roads, from the end of April through December.

Results

43/51 sites (84.3%) were found positive for sand flies. The 2006 collections accounted for a total of 4341 specimens including six species. Among competent Leishmania vector species, P. perniciosus was the most prevalent (36.5%) being identified in all sand fly-positive sites, with significant abundance in those of the old city centre. Other species of interest were P. sergenti (2.5%) and P. neglectus (1.5%). The 2013 survey produced 1130 sand flies, of which 39.5% were P. perniciosus, 1.6% P. sergenti and 0.7% P. neglectus. A search for Leishmania DNA in a small sample of 72 P. perniciosus females revealed 11% infection prevalence.

Conclusions

Our findings from an old urban focus of leishmaniasis demonstrate that phlebotomine sand flies have adapted fairly well to the drastic environmental changes that have occurred in cities of the Western world in the past century and still represent a potential risk for Leishmania transmission.

Evaluation of indirect immunofluorescence antibody test and enzyme-linked immunosorbent assay for the diagnosis of infection by Leishmania infantum in clinically normal and sick cats

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IFAT for anti-Leishmania IgG was positive in 10/100 cats.

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ELISA for anti-Leishmania IgG was positive in 1/100 cats.

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IFAT for anti-Leishmania IgM was positive in 1/100 cats.

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The results of IFAT and ELISA for anti-Leishmania IgG disagreed (P = 0.039).

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IFAT or ELISA for anti-Leishmania IgG disagreed with the results of PCR.

Cats that live in areas where canine and human leishmaniosis due to Leishmania infantum is endemic may become infected and may develop anti-Leishmania antibodies. In this study 50 clinically normal and 50 cats with cutaneous and/or systemic signs that lived in an endemic area and had been previously examined for infection by L. infantum using PCR in four different tissues were serologically tested for the presence of anti-Leishmania IgG (IFAT and ELISA) and IgM (IFAT). The aim was to compare the results of IFAT, ELISA and PCR and to investigate the possible associations between seropositivity to Leishmania spp and signalment, living conditions, season of sampling, health status of the cats, and seropositivity to other infectious agents. Low concentrations of anti-Leishmania IgG were detected by IFAT in 10% of the cats and by ELISA in 1%, whereas anti-Leishmania IgM were detected by IFAT in 1%. There was disagreement between the results of IFAT and ELISA for anti-Leishmania IgG (P = 0.039) and between all serological tests and PCR (P < 0.001). The diagnostic sensitivity of all serological tests, using PCR as the gold standard, was very low, but ELISA and IFAT for anti-Leishmania IgM had 100% specificity. The diagnostic sensitivity of all serological tests could not be improved by changing the cut-off values. Seropositivity for Leishmania spp was not associated with signalment, living conditions, season of sampling and health status of the cats or with seropositivity to feline leukemia virus, feline immunodeficiency virus, feline coronavirus, Toxoplasma gondii and Bartonella henselae. In conclusion, because of their low sensitivity and very high specificity two of the evaluated serological tests (ELISA for anti-Leishmania IgG and IFAT for anti-Leishmania IgM) may be useless as population screening tests but valuable for diagnosing feline infection by L. infantum.

Wild and synanthropic reservoirs of Leishmania species in the Americas

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Leishmania parasites are maintained by multiple hosts included in seven mammal orders.

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Reservoir hosts are the assemblage of species responsible for Leishmania maintenance.

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Mammal host–Leishmania interaction determines host competence to infect vectors.

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Associate ecological and parasitological data are crucial to understand the wild cycle.

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Prevention of human cases is dependent on a thorough knowledge of the wild cycle.

The definition of a reservoir has changed significantly in the last century, making it necessary to study zoonosis from a broader perspective. One important example is that of Leishmania, zoonotic multi-host parasites maintained by several mammal species in nature. The magnitude of the health problem represented by leishmaniasis combined with the complexity of its epidemiology make it necessary to clarify all of the links in transmission net, including non-human mammalian hosts, to develop effective control strategies. Although some studies have described dozens of species infected with these parasites, only a minority have related their findings to the ecological scenario to indicate a possible role of that host in parasite maintenance and transmission. Currently, it is accepted that a reservoir may be one or a complex of species responsible for maintaining the parasite in nature. A reservoir system should be considered unique on a given spatiotemporal scale. In fact, the transmission of Leishmania species in the wild still represents an complex enzootic “puzzle”, as several links have not been identified. This review presents the mammalian species known to be infected with Leishmania spp. in the Americas, highlighting those that are able to maintain and act as a source of the parasite in nature (and are thus considered potential reservoirs). These host/reservoirs are presented separately in each of seven mammal orders – Marsupialia, Cingulata, Pilosa, Rodentia, Primata, Carnivora, and Chiroptera – responsible for maintaining Leishmania species in the wild.

Current status of L. infantum infection in stray cats in the Madrid region (Spain): implications for the recent outbreak of human leishmaniosis?

Background

Since 2009, the incidence of human leishmaniosis in the SW of the Madrid region has been unusually high. Although dogs are the main reservoir for this disease, a role played by dogs in this outbreak has been ruled out and investigators are now considering other hosts (eg. cats, rabbits, hares) as possible alternative reservoirs.

This study was designed to examine the Leishmania infantum status of stray cats in Madrid to assess its possible implications in the human leishmaniosis outbreak.

Methods

346 captured stray cats were tested for antibodies against L. infantum by the indirect fluorescent antibody technique (IFAT) and nested-PCR methods were used to detect Leishmania DNA in blood samples of cats testing seropositive for L. infantum and/or retroviruses infection. Cats were also tested for Toxoplasma gondii using the direct agglutination test (DAT) and feline leukemia virus (FeLV) antigen and feline immunodeficiency virus (FIV) antibodies (PetChek* FIV/FeLV). The presence of intestinal parasites was determined using a routine coprological method.

Results

The seroprevalence of L. infantum infection (cut off ≥ 1/100) was 3.2% (11/346). However, it was not possible to amplify Leishmania DNA in any of the blood samples. Seropositivity was not associated with sex, age, capture site, clinical status, retrovirus infection or T. gondii seropositivity. Of the 11 cats seropositive for L. infantum, 3 also tested positive for FIV, none for FeLV and 6 for T. gondii. It should be mentioned that the prevalence of FeLV p27 antigen was 4% and of FIV antibody was 9.2%. Although the seroprevalence of T. gondii was quite high at 53.5%, no T. gondii oocysts were found in any of the faeces samples analysed (n = 287). In contrast, intestinal parasites were detected in 76 (26.5%) samples, Toxocara cati being the most prevalent.

Conclusions

Our results suggest a stable L. infantum infection situation among the stray cats of the Madrid area; the disease is uncommon and no clinical cases have been reported to date. The detection of other zoonotic parasites such as T. gondii and T. cati in stray cats indicates a need to adopt strict control measures in this population.