A case report of acute claudication due to vena cava thromboembolism in a dog naturally infected with Leishmania Infantum.

Canine leishmaniosis is a vector-borne disease caused by Leishmania infantum, and clinical manifestations of infection range from absent or severe to fatal and result from immune-mediated mechanisms. In dogs, the most common clinical signs of leishmaniosis include skin lesions and lymphadenomegaly. However, the presence of other nontypical signs has been described, and diagnosing these cases can be challenging. The aim of the present short communication was to describe the impact of the formation of circulating immunocomplexes due to L. infantum in a dog with leishmaniosis affected by a massive venous thrombus of the caudal vena cava and external iliac veins. On admission, the dog presented bilateral cutaneous vasculopathy of the thigh and renal disease due to L. infantum infection. Two weeks after starting anti-Leishmania treatment based on meglumine antimoniate and allopurinol administration, the animal developed acute claudication of the hind limbs with the presence of a thrombus in the caudal vena cava and the external iliac veins and a high level of circulating immunocomplexes detected by enzyme-linked immunosorbent assay. Exacerbation of the humoral immune response, along with deposition of circulating immune complexes in the tissues and the concurrent presence of kidney and liver damage, might have contributed to an imbalance in haemostasis in this patient. Future studies should evaluate and analyse the pathological mechanisms contributing to thrombosis in dogs with leishmaniosis.

Hyperbetaglobulinemia, anaemia and thrombocytopenia in a domestic ferret (Mustela putorius furo) associated to Leishmania infantum.

Leishmaniosis in domestic ferrets is a vector-borne disease caused in Europe by the protozoan parasite Leishmania infantum. There is limited information on clinical signs and laboratory abnormalities in ferrets due to leishmaniosis. This clinical case report described a domestic ferret (Mustela putorius furo) with severe hyperbetaglobulinemia, anaemia, thrombocytopenia, and abnormal renal parameters. A good clinical response following an anti-Leishmania infantum treatment protocol was achieved. However, the presence of pain at the site of injection was the main side effect due to meglumine antimoniate administration. Xanthine crystalluria was not observed in urine sediment with no other urine alterations detected by urine analysis during the follow-up. Initially, clinical signs noted in this ferret could not initially be attributed to leishmaniosis. However, no causes were found that could have caused the hyperglobulinemia in this patient. A reduction of the levels of anti-L. infantum serum antibodies and the concentrations of beta-globulin fraction was detected in this patient after anti-Leishmania treatment administered as well as the disappearance of thrombocytopenia. To extent of the knowledge of leishmaniosis in ferrets, this is the fourth case report of leishmaniosis documented in this species.

Presence of anti-Leishmania infantum antibodies in sheep (Ovis aries) in Spain.

Sandflies are the primary transmission vector for Leishmania spp parasite in endemic regions. The role of other animals, different from the dog, is under discussion in the leishmaniosis endemic countries. A limited number of reports have been published on the possible role of livestock in European countries for Leishmania maintenance and diffusion. The aim of the present study was to perform a serosurvey on sheep in areas of Spain that are endemic for zoonotic leishmaniosis and establish the possible role of sheep regarding Leishmania infantum infection in endemic areas. Three hundred and two serum samples were obtained from sheep and were evaluated for serological survey to detect L. infantum by using the in-house ELISA technique. Twenty-eight out of the 302 samples included in this study, were positive for L. infantum antibodies (9.27%). In the present study, a significant association was found between adult age and seropositivity (p = 0.006) and female gender and seropositivity (p = 0.02). This association has not been previously described in other European studies related to L. infantum infection in sheep. Our study reveals that domestic sheep in a European Mediterranean country are exposed to L. infantum. To our knowledge, this study demonstrates the presence of seropositive sheep in different regions of Spain for the first time. Further epidemiological studies focus on evaluating the rural cycle of this parasite to know if livestock could act as a potential reservoir are needed.

First report on natural infection by Dirofilaria repens in a cat in Spain: case report and literature review of feline subcutaneous dirofilariosis in Europe.

Dirofilaria repens is an endemic mosquito-borne pathogen widely spread throughout Europe and other non-Europen regions. Infection by D. repens has been reported in dogs, although little is known about the occurrence and epidemiological features of this nematode in cats. During the surgical procedure within the framework of a trap, neuter and release sterilization program, two female filarial nematodes with spontaneous movement were removed from the internal part of the spermatic cord from asymptomatic stray cat in Spain (Grao de Castellón, Castellon de la Plana, province of Spain). Moreover, the presence of microfilariae was detected by using three different methods, including direct blood smear technique, the microhematocrit tube test, and Knott´s modified test. PCR performed from the nematodes extracted from the spermatic cord and from microfilariae in EDTA-blood sample tested both positive for D. repens. To the authors' knowledge, this is the first report that demonstrates the presence of D. repens in cats in Spain. In this sense, a review of the current scientific status of feline subcutaneous dirofilariosis in Europe was also performed. Future investigations should analyze the epidemiological role of cats in D. repens infection including the prevalence of infection. Veterinarians working in endemic areas should be aware of this infection in cats and their susceptibility.

Molecular survey on vector-borne pathogens in clinically healthy stray cats in Zaragoza (Spain).

BACKGROUND: In Europe, feline vector-borne infections are gaining importance because of the changing climate, expanding habitats of potential vectors and expanding pathogen reservoirs. The main objective of this study was to assess the prevalence of vector-borne pathogens (VBPs) in stray cats in Zaragoza, Spain, and to investigate potential risk factors for infection, including feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV). METHODS: Blood samples from stray cats presented to the veterinary faculty in Zaragoza between February 2020 and 2022 were tested by polymerase chain reaction (PCR) for the presence of Anaplasma phagocytophilum, Anaplasma platys, Bartonella henselae, Ehrlichia canis, Rickettsia spp., haemotropic Mycoplasma spp., Hepatozoon spp., Leishmania infantum, piroplasms and microfilariae at the LABOKLIN laboratory. The cats were also tested for FeLV and FIV by PCR. RESULTS: Nearly half of the cats (158/332, 47.6%) were positive for at least one VBP. Hepatozoon spp. were detected in 25.6%, haemotropic Mycoplasma spp. in 22.9%, B. henselae in 9.3% and L. infantum in 2.1% of the cats. Male sex had a statistically significant association with test results for haemotropic Mycoplasma spp. (odds ratio 1.38 [1.21;1.57]); regionality with Hepatozoon spp., B. henseale and FIV; and seasonality with Hepatozoon spp., haemotropic Mycoplasma spp., L. infantum and FeLV (P ≤ 0.05 each). A strong positive correlation was reported for the amount of rainfall and the number of cats that tested positive for Hepatozoon spp. (ρ = 753, P = 0.05). None of the cats tested positive for A. phagocytophilum, A. platys, E. canis, Rickettsia spp., piroplasms, or microfilariae. Co-infections with multiple VBPs were detected in 56 out of 332 cats (16.9%). Thirty-one of the 332 cats included in the study (9.3%) tested positive for FeLV (6.9%) and for FIV (3.6%). In 20/31 cats (64.5%) that tested positive for FeLV/FIV, coinfections with VBP were detected (P = 0.048, OR 2.15 [0.99; 4.64]). CONCLUSIONS: VBPs were frequently detected in stray cats in Zaragoza. In particular, regionality and seasonality had a statistically significant association with PCR results for most VBPs included in the study.

Serological exposure to influenza A in cats from an area with wild birds positive for avian influenza.

Influenza A is an emerging zoonotic virus with worldwide distribution. To our knowledge, no studies have been conducted to assess influenza A exposure in stray cats in regions with positive cases of wild birds. This study aimed to determine the seroprevalence of anti-influenza A antibodies in feral cats from a region in Spain with cases of positive wild birds. A cross-sectional study of stray cats (n = 183) was conducted between March 2022 and March 2023. The presence of antibodies against the influenza A virus was tested using a commercial enzyme-linked immunosorbent assay kit adapted for this study and confirmed by competitive enzyme-linked immunosorbent assay for the detection of antibodies against the haemagglutinin H5. During sample collection, none of the cats exhibited clinical signs of illness. Four of the 183 animals tested showed anti-influenza A antibodies by ELISA, and the seroprevalence of influenza A was 2.19% (95% confidence interval 0.85%-5.48%). Due to the low number of positive cases detected, it appears that cats did not have an important epidemiological role in influenza A transmission during this period.

Non-controlled, open-label trial to assess clinical and immunological parameters in atopic dogs feeding monoprotein grain free diet versus a standard grain diet.

Canine atopic dermatitis (cAD) is a common inflammatory skin disease that is treated with medicines or allergen-specific immunotherapy. An improvement diet can help treatment of cAD. The purpose of this study was compare two diets on clinical and immunological parameters in atopic dogs without food hypersensitivity. Diet A, a commercial based on rice, was offered to 22 atopic dogs during 30 days and Diet B (grain free, rich in salmon) was given to 8 atopic dogs. Clinical scores were assessed by CADESI-4 and PVAS at the beginning (T0) and at the end of the study (T30). CD4+ and CD8+ were measured in PBMCs, and serum cytokines (TNF-α, IL-10, IL-31 and IL-34) were determined. Both diets decreased CADESI-4 score and Diet A decreased PVAS score (p < 0.05). There were no statistical significant differences between diets at T30 for CD4+ and CD8+. A decrease in the IL-31 concentrations and increase in IL-10 levels (p < 0.05) was observed with Diet A at T30. There were no differences between any of the two diets when the other results at T0 and T30 were compared for any of the parameters analysed. In conclusion, the results indicate that dietary intervention had not influence on cellular component of the immune system, but a positive effect was observed on IL-31, IL-10 serum levels for Diet A. Further studies are needed to enrich dietary components of the food for atopic dogs without food hypersensibility to help improvement the management of the cAD.

Evaluation of an immunochromatographic serologic test to detect the presence of anti-Toxoplasma gondii antibodies in cats.

BACKGROUND: Toxoplasmosis is a protozoan disease caused by Toxoplasma gondii. Different T. gondii confirmatory techniques, including serologic methods, are available to detect the presence of the parasite. Among serology techniques, immunochromatographic rapid testing could be a reliable alternative to serologic laboratory techniques. OBJECTIVE: This study evaluated a commercial immunochromatographic test (FASTest TOXOPLASMA g) in seronegative and seropositive cats. METHODS: Two indirect immunofluorescence antibody reference tests, an in-house technique, and a commercial test were used to classify 292 feline serum samples. The rapid test was evaluated in different groups of cats, including healthy seronegative cats (n = 121), seropositive cats with variable anti-Toxoplasma antibodies (n = 146), and cats with positive serologic results for other pathogens (n = 25). The sensitivity, specificity, accuracy, receiver operating characteristic curves, and kappa statistics were analyzed as performance measures. RESULTS: Of the 292 samples, 146 were classified as T. gondii seropositive and 146 as T. gondii seronegative. Concordant results were obtained for all samples using immunofluorescence antibody tests. The diagnostic measures of this rapid test showed 98.63% sensitivity and 100% specificity, and 99.32% accuracy. The kappa statistics value was 0.986, and the area under the receiver operating characteristic curve was 0.993. CONCLUSIONS: This rapid test showed diagnostic measurements similar to those of traditional quantitative serologic methods. In situations where laboratory techniques are not available, this test, under clinical conditions, could be a useful alternative to obtain accurate results rapidly.

A cross-sectional serosurvey of SARS-CoV-2 and co-infections in stray cats from the second wave to the sixth wave of COVID-19 outbreaks in Spain.

Severe Acute Respiratory Syndrome Coronavirus 2 is the causative agent of Coronavirus Disease 2019 in humans. Among domestic animals, cats are more susceptible to SARS-CoV-2 than dogs. The detection of anti-SARS-CoV-2 antibodies in seemingly healthy cats and/or infected cats which are in close contact with infected humans has been described. The presence of animals that tested positive by serology or molecular techniques could represent a potential transmission pathway of SARS-CoV-2 that can spill over into urban wildlife. This study analyses the seroprevalence variation of SARS-CoV-2 in stray cats from different waves of outbreaks in a geographical area where previous seroepidemiological information of SARS-CoV-2 was available and investigate if SARS-CoV-2-seropositive cats were exposed to other co-infections causing an immunosuppressive status and/or a chronic disease that could lead to a SARS-CoV-2 susceptibility. For this purpose, a total of 254 stray cats from Zaragoza (Spain) were included. This analysis was carried out by the enzyme-linked immunosorbent assay using the receptor binding domain of Spike antigen and confirmed by serum virus neutralization assay. The presence of co-infections including Toxoplasma gondii, Leishmania infantum, Dirofilaria immitis, feline calicivirus, feline herpesvirus type 1, feline leukemia virus and feline immunodeficiency virus, was evaluated using different serological methods. A seropositivity of 1.57% was observed for SARS-CoV-2 including the presence of neutralizing antibodies in three cats. None of the seropositive to SARS-CoV-2 cats were positive to feline coronavirus, however, four SARS-CoV-2-seropositive cats were also seropositive to other pathogens such as L. infantum, D. immitis and FIV (n = 1), L. infantum and D. immitis (n = 1) and L. infantum alone (n = 1).Considering other pathogens, a seroprevalence of 16.54% was detected for L. infantum, 30.31% for D. immitis, 13.78%, for T. gondii, 83.86% for feline calicivirus, 42.52% for feline herpesvirus type 1, 3.15% for FeLV and 7.87% for FIV.Our findings suggest that the epidemiological role of stray cats in SARS-CoV-2 transmission is scarce, and there is no increase in seropositivity during the different waves of COVID-19 outbreaks in this group of animals. Further epidemiological surveillances are necessary to determine the risk that other animals might possess even though stray cats do not seem to play a role in transmission.

Molecular and Serological Studies on Potential SARS-CoV-2 Infection among 43 Lemurs under Human Care-Evidence for Past Infection in at Least One Individual.

In the setting of the recent COVID-19 pandemic, transmission of SARS-CoV-2 to animals has been reported in both domestic and wild animals and is a matter of concern. Given the genetic and functional similarities to humans, non-human primates merit particular attention. In the case of lemurs, generally considered endangered, they are believed to be susceptible to SARS-CoV-2 infection. We have conducted a study for evidence of SARS-CoV-2 infection among the 43 lemurs of Mundomar, a zoological park in Benidorm, Spain. They belong to two endangered lemur species, 23 black-and-white ruffed lemurs (Varecia variegata) and 20 ring-tailed lemurs (Lemur catta). Health assessments conducted in 2022 and 2023 included molecular analyses for SARS-CoV-2 RNA of oral and rectal swabs using two different RT-qPCR assays, always with negative results for SARS-CoV-2 in all animals. The assessment also included serological testing for antibodies against the receptor-binding domain (RBD) of the spike protein (S) of SARS-CoV-2, which again yielded negative results in all animals except one black-and-white ruffed lemur, supporting prior infection of that animal with SARS-CoV-2. Our data, while not indicating a high susceptibility of lemurs to SARS-CoV-2 infection, show that they can be infected, adding to the existing information body on potential ways for SARS-CoV-2 virus spreading in zoos, highlighting the need for animal surveillance for the virus.

First serological study of Dirofilaria immitis antibodies in household domestic ferrets (Mustela putorius furo) in southern Spain - Short communication.

Dirofilaria immitis is an endemic mosquito-borne pathogen widely spread throughout Europe as well as North and South America. Infection by D. immitis has been reported in domestic ferrets, although little is known about the occurrence and the epidemiological features of this nematode in this species. The aim of the present retrospective study was to assess the prevalence of D. immitis antibodies using an in-house enzyme-linked immunosorbent assay specifically developed for use in ferrets. One hundred and eighty-six serum samples were obtained from the Province of Valencia (Spain), an area endemic for dirofilariosis. Of the 186 serum samples included in the study, 27 (14.51%) were classified as D. immitis seropositive and 159 samples as D. immitis seronegative. The results provide valuable information on the seroprevalence of D. immitis infection in domestic ferrets in an area endemic for this vector-borne pathogen. The presence of seropositive ferrets should be taken into account and preventive measures should be implemented, including the possibility of serological screening for the early detection of Dirofilaria antibodies as a serological marker of exposure. This is the first study that demonstrates the presence of D. immitis exposure in ferrets in Spain. Veterinarians working in endemic areas should be aware of this infection in ferrets and their susceptibility.

No Evidence of SARS-CoV-2 Infection in Wild Mink (Mustela lutreola and Neogale vison) from Northern Spain during the First Two Years of Pandemic.

The impact of the SARS-CoV-2 pandemic on wildlife is largely unevaluated, and extended surveillance of animal species is needed to reach a consensus on the role of animals in the emergence and maintenance of SARS-CoV-2. This infection has been detected in farmed and domestic animals and wild animals, mainly in captivity. The interactions or shared resources with wildlife could represent a potential transmission pathway for the SARS-CoV-2 spill over to other wild species and could lead to health consequences or the establishment of new reservoirs in susceptible hosts. This study evaluated the presence of SARS-CoV-2 in European mink (Mustela lutreola) and American mink (Neogale vison) in Spain by enzyme-linked immunosorbent assay (ELISA) using the receptor binding domain (RBD) of Spike antigen in serum samples and/or by RT-qPCR assays in oropharyngeal and rectal swabs. From January 2020 to February 2022, a total of 162 animals (127 European mink and 35 American mink) with no evidence of SARS-CoV-2 infection were included in the study. Antibodies against the SARS-CoV-2 were not found in the serum samples analysed (n = 126), nor was the virus amplified by RT-qPCR (n = 160 swabs). Our results suggest that the potential role of wild mink and the European mink bred in captivity and released to the wild as dispersers of SARS-CoV-2 is so far low. However, wildlife surveillance for early detection of human and animal risks should be continued. In this sense, epidemiological monitoring measures, including serology and molecular analysis, are necessary.

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.

Comparison of circulating CD4+, CD8+ lymphocytes and cytokine profiles between dogs with atopic dermatitis and healthy dogs.

INTRODUCTION: Canine atopic dermatitis (cAD) is an inflammatory skin disease characterized by impaired immune function. Changes in the proportions of CD4+ and CD8+ lymphocytes and the serum concentrations of cytokines in the pathogenesis of cAD have been described. OBJECTIVES: To assess whether the changes in the ratio of CD4+ and CD8+ lymphocytes in the peripheral blood of atopic dogs at the time of diagnosis are related to the severity of the disease. Furthermore, we determined whether the changes in the serum concentrations of the cytokines IL-31, IL-34, IL-10, IFN-γ, and TNF-α were different between atopic and control dogs. PROCEDURES: Fifty-six client-owned dogs with atopic dermatitis and 53 healthy control dogs were used. The percentages of CD4+ and CD8+ lymphocytes were determined by imaging flow cytometry. The index of CADESI-03 was calculated. Serum cytokine levels were analyzed using ELISA. RESULTS: Atopic dogs showed a higher percentage of CD8+ lymphocytes, a lower CD4+/CD8+ ratio than healthy dogs, and a positive correlation with CADESI-03. Atopic dogs also showed higher serum IL-31 and IL-34 levels and lower IL-10 levels. A moderate positive correlation was found between serum IL-31 and CADESI-03. CONCLUSIONS: The CD4+/CD8+ ratio may be a sensitive parameter that positively correlates with the severity of cAD, and elevated serum levels of IL-31 and IL-34 may facilitate diagnosis of the disease.

Evaluation of five different rapid immunochromatographic tests for canine leishmaniosis in Spain.

Canine leishmaniosis is a vector-borne disease caused by Leishmania parasites. Serological methods are the most common tests used for the diagnosis. This study aimed to evaluate and compare different serological commercial immunochromatographic rapid tests available in Spain to detect anti-Leishmania canine antibodies. The immunochromatographic tests were evaluated in different groups of dogs (healthy seronegative dogs (n = 21), naturally-sick dogs with moderate anti-Leishmania antibodies (n = 39), naturally-sick dogs with high anti-Leishmania antibodies (n = 37), dogs with the serological result of other pathogens infection (n = 20) and exposed dogs (n = 33)) admitted to the Veterinary Teaching Hospital of the University of Zaragoza (Spain) according to the clinical information sent with the sample to the laboratory for diagnostic purposes. The serology status was also routinely recorded through an in-house enzyme-linked immunosorbent assay (ELISA) and an in-house indirect immunofluorescence test (IFAT). The qualitative commercial serological immunochromatographic tests used were: FASTest LEISH, Uranotest Leishmania, Uranotest Leishmania 2.0, Speed Leish K, Witness Leishmania, and DFV Test Leishmania. Performance measures analyzed for each test were: sensitivity, specificity, and area under the receiver-operating (ROC) curve. The maximum specificity (1.00) was attained for Uranotest Leishmania and DFT Test Leishmania, followed by FASTest LEISH (0.98), Uranotest Leishmania 2.0 (0.98), Speed Leish K (0.98), and Witness Leishmania (0.95). The maximum sensitivity was attained for FASTest LEISH (1.00), followed by Uranotest 2.0 (0.97), Speed Leish K (0.97), Uranotest (0.96), and the lowest results with Witness (0.84) and DFV Test (0.59). Regarding the ROC curve, the maximum value was attained with the FASTest LEISH (0.99), followed by Uranotest (0.98), Uranotest 2.0 (0.97), Speed Leish K (0.97), Witness (0.90), and the lowest result with DFV Test (0.79). Efforts in the field of diagnosis should focus on establishing a commercial immunochromatographic test with high sensitivity and specificity with a reasonable cost-benefit balance.

Leishmaniosis caused by Leishmania infantum in ferrets: Update review.

Leishmaniosis in domestic ferrets (Mustela putorius furo) is a disease caused by Leishmania infantum, a parasite transmitted through the bite of an infected female phlebotomine sand fly. Among vertebrates, the dog is the primary domestic reservoir of the parasite; however, other domestic animals can be implicated such as cats. The first description of a clinical case of leishmaniosis in domestic ferrets was reported recently. As a result, new knowledge has been published including empirically based treatment protocols, confirmatory techniques to detect the presence of the parasite infection and seasonal variation in the antibodies against Leishmania in apparently healthy domestic ferrets. The most common clinical signs observed are enlargement of peripheral lymph nodes and skin lesions such as papular and/or ulcerative dermatitis. Additionally, the most frequent laboratory alterations seen are hyperproteinaemia with hyperglobulinaemia and biochemical analytes alterations depending on the affected tissue. Two different therapeutic protocols have been described to treat domestic ferrets with leishmaniosis: meglumine antimoniate plus allopurinol protocol or miltefosine plus allopurinol protocol. These treatment protocols seemed to be able to control the Leishmania infection, although the presence of xanthinuria could be detected. The susceptibility of domestic ferrets to Leishmania infantum, the clinical picture, treatment of infected animals and prevention are poorly understood, due to the scarcity of recent description in the literature. Different proposed diagnostic algorithms have been included for domestic ferrets with suspected leishmaniosis, clinically healthy domestic ferrets and animals as blood donors. In this sense, the present review provides updated data on scientific knowledge of leishmaniosis in ferrets.

Serological evidence of SARS-CoV-2 and co-infections in stray cats in Spain.

A new coronavirus known as SARS-CoV-2 emerged in Wuhan in 2019 and spread rapidly to the rest of the world causing the pandemic disease named coronavirus disease of 2019 (COVID-19). Little information is known about the impact this virus can cause upon domestic and stray animals. The potential impact of SARS-CoV-2 has become of great interest in cats due to transmission among domestic cats and the severe phenotypes described recently in a domestic cat. In this context, there is a public health warning that needs to be investigated in relation with the epidemiological role of this virus in stray cats. Consequently, in order to know the impact of the possible transmission chain, blood samples were obtained from 114 stray cats in the city of Zaragoza (Spain) and tested for SARS-CoV-2 and other selected pathogens susceptible to immunosuppression including Toxoplasma gondii, Leishmania infantum, feline leukaemia virus (FeLV) and feline immunodeficiency virus (FIV) from January to October 2020. Four cats (3.51%), based on enzyme-linked immunosorbent assay (ELISA) using the receptor binding domain (RBD) of Spike antigen, were seroreactive to SARS-CoV-2. T. gondii, L. infantum, FeLV and FIV seroprevalence was 12.28%, 16.67%, 4.39% and 19.30%, respectively. Among seropositive cats to SARS-CoV-2, three cats were also seropositive to other pathogens including antibodies detected against T. gondii and FIV (n = 1); T. gondii (n = 1); and FIV and L. infantum (n = 1). The subjects giving positive for SARS-CoV-2 were captured in urban areas of the city in different months: January 2020 (2/4), February 2020 (1/4) and July 2020 (1/4). This study revealed, for the first time, the exposure of stray cats to SARS-CoV-2 in Spain and the existence of concomitant infections with other pathogens including T. gondii, L. infantum and FIV, suggesting that immunosuppressed animals might be especially susceptible to SARS-CoV-2 infection.

Absence of SARS-CoV-2 Antibodies in Natural Environment Exposure in Sheep in Close Contact with Humans.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the zoonotic causative agent of coronavirus disease 2019 (COVID-19) that has caused a pandemic situation with millions of infected humans worldwide. Among domestic animals, there have been limited studies regarding the transmissibility and exposure to the infection in natural conditions. Some animals are exposed and/or susceptible to SARS-CoV-2 infection, such as cats, ferrets and dogs. By contrast, there is no information about the susceptibility of ruminants to SARS-CoV-2. This study tested the antibody response in 90 ovine pre-pandemic serum samples and 336 sheep serum samples from the pandemic period (June 2020 to March 2021). In both cases, the animals were in close contact with a veterinary student community composed of more than 700 members. None of the serum samples analyzed was seroreactive based on an enzyme-linked immunosorbent assay (ELISA) using the receptor-binding domain (RBD) of the spike antigen. In this sense, no statistical difference was observed compared to the pre-pandemic sheep. Our results suggest that it seems unlikely that sheep could play a relevant role in the epidemiology of SARS-CoV-2 infection. This is the first study to report the absence of evidence of sheep exposure to SARS-CoV-2 in natural conditions.

Prevalence of microfilariae, antigen and antibodies of feline dirofilariosis infection (Dirofilaria immitis) in the Zaragoza metropolitan area, Spain.

Feline heartworm disease is a vector-borne parasitical disease caused by Dirofilaria immitis. Heartworm infection in dogs is prevalent in the Mediterranean countries. Information about the geographical distribution and epidemiological features of D. immitis infection in cats is scarce, particularly in urban stray cats that live within endemic regions for canine heartworm disease. The aim of the current study was to determine the seroprevalence of antigen and antibodies to D. immitis in feral cats in Zaragoza city, an endemic region of Spain. For this purpose, blood samples were examined for microfilariae using a direct blood smear technique and the modified Knott test. Two serological techniques for anti-D. immitis antibody detection (Solo Step® FH and in-house ELISA) and three different commercial antigen tests (DiroChek®, MegaELISA® DIRO Antigen and FASTest® HW) were performed. Blood samples from 250 stray cats were tested: 61 cats (24.40%) tested positive by the in-house ELISA, and 9 cats gave positive (3.6%) results with Solo Step® FH. The global seroprevalence of D. immitis in the feline population of the studied area of Zaragoza was 25.20% (63/250) including Solo Step® FH result and in-house ELISA. The blood exam for all samples was negative when evaluating for microfilariae and not a single cat was positive for antigen testing. This study demonstrates the presence of D. immitis infection in Zaragoza city. Veterinarians working in endemic areas should be aware of this infection in cats at risk and their susceptibility.