Feline Immunodeficiency Virus Research Articles

Transfusion transmissible pathogens are prevalent in healthy cats eligible to become blood donors.

This study aims to determine the prevalence of subclinical infectious agents considered core pathogens for worldwide screening in healthy, client-owned, indoor cats eligible to become blood donors in Spain and Portugal. Blood samples of healthy, indoor, domestic cats selected to be potential blood donors were tested for feline leukaemia virus antigens, feline immunodeficiency virus antibodies and polymerase chain reactions for Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, feline leukaemia virus provirus, Leishmania spp. and Bartonella spp. Not all donors were tested for all agents. Overall, 5105 healthy indoor cats were tested and 8.1% (414/5105) had at least one subclinical infectious agent that is transmissible through blood product transfusion. 1.5% (77/5105) were positive for feline leukaemia virus antigens and 2.9% (148/5105) were positive for feline immunodeficiency virus antibodies, therefore they were excluded as donors. The overall prevalence of haemoplasmas in feline leukaemia virus and feline immunodeficiency virus SNAP-negative feline blood donors was 3.7% (181/4880) [1.3% (63/4880) were positive for Mycoplasma haemofelis; 2.3% (112/4880) to Candidatus Mycoplasma haemominutum and 0.12% (6/4880) to Candidatus Mycoplasma turicensis]. The prevalence of feline leukaemia provirus was 5.2% (9/173) and of Bartonella spp. was 0.2% (2/1122). None of the 173 cats were positive for Leishmania spp. The prevalence of many transfusion transmissible pathogens was relatively high in this healthy, client-owned, indoor cats eligible to become blood donors. Performing an extended screening panel that includes at least polymerase chain reactions for Mycoplasma haemofelis, Candidatus Mycoplasma haemominutum, Candidatus Mycoplasma turicensis, feline leukaemia virus provirus, and Bartonella spp., in addition to feline leukaemia virus antigens and feline immunodeficiency virus antibodies, is recommended in pet blood banks from analogous regions.

Molecular Mechanisms of Feline Cancers

Feline cancers have not been studied as extensively as canine cancers, though they may offer similar advantages, with cats being immunocompetent animals subject to similar conditions as their human counterparts. The most common feline cancers include lymphoma, squamous cell carcinoma, sarcoma, and mammary tumors, though mast cell tumors were also investigated in this review. As the pathogenesis of many feline cancers remains unclear, this study seeks to elucidate some molecular mechanisms behind feline cancers. Feline lymphoma has been commonly associated with feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV), though in recent years it has appeared more as lymphoma of the gastrointestinal tract. Chromosomal alterations (translocations) due to the virus-associated lymphoma, as well as aberrant gene expression (such as in COX-2 and MDR1) have been identified in the past. While feline lymphoma may be divided into many subtypes, feline sarcoma may be divided into two broad classifications of feline injection site associated (FISS) sarcoma and spontaneous sarcoma, with FISS being a potential model for inflammation leading to tumorigenesis in humans. Previous studies have found multiple chromosomal alterations (including aneuploidy and chromosomal translocations), as well as aberrations in gene expression in feline sarcoma. In the past, oral squamous cell carcinoma has been proposed as a model for human head and neck cancer, and mammary tumors have been proposed as a model for human breast cancers due to similar prognosis and phenotype, as well as higher rate of occurrence in cats than in humans. Mutations have been identified in genes such as TP53, ERBB2, and TWIST1 in feline mammary tumors. c-KIT mutations were commonly located in feline mast cell tumors, though these findings were not particularly significant in terms of correlation to other prognostic indicators. This review seeks to elucidate pathways and treatments for feline cancers for the field of comparative genomics and oncology.

The incidence of aggressive behavior in cats naturally infected with Feline Immunodeficiency Virus (FIV) and its interaction with FIV disease progression.

A study was undertaken to determine the possible interaction between aggressive behavior and Feline immunodeficiency virus (FIV) disease progression based on semi‑quantitative viral load levels and health status in naturally FIV‑infected cats. FIV status was determined in ninety‑six owned and stray cats, using nested polymerase chain reaction (PCR). Aggressive tendencies were assessed based on observation and the cats' demeanor as determined by the owners and shelter caretakers. Results showed that forty‑seven cats (49%) were PCR‑positive for FIV infection and all aggressive cats were FIV‑positive (100%). FIV infection was significantly linked to extreme aggressive tendencies and the extremely aggressive FIV‑infected cats were more likely to have an unhealthy status compared to the non‑aggressive individuals (p = 0.022). There was also a significant difference (p = 0.012) in the mean Cycle threshold (Ct) values between the aggressive and non‑aggressive FIV‑infected cats and also between the unhealthy FIV‑infected cats with extreme aggressive tendencies and the healthy FIV‑infected individuals without aggression (p = 0.001). Accordingly, results indicated that parameters associated with FIV disease progression are directly linked to aggression. The possible impact of FIV on the behavioral pattern of naturally infected cats should not be underestimated. However, there is an urgent need to conduct more experiments to support the assumptions about the possible exacerbation of aggression tendencies in naturally FIV‑infected cats following the direct effect of FIV through the course of the infection.

Transcriptional inhibition of feline immunodeficiency virus by alpha-amanitin.

Alpha-amanitin, one of the amatoxins in egg amanita, has a cyclic peptide structure, and was reported as having antiviral activity against several viruses. We investigated whether α-amanitin has antiviral activity against feline immunodeficiency virus (FIV). FL-4 cells persistently infected with FIV Petaluma were cultured with α-amanitin. Reverse transcriptase (RT) activity in the supernatant of FL-4 cells was significantly inhibited by α-amanitin. In addition, the production of FIV core protein in FL-4 cells was inhibited by α-amanitin when analyzed by western blotting. Furthermore, α-amanitin inhibited the transcription of FIV in real-time RT-PCR. These data suggested that α-amanitin showed anti-FIV activity by inhibiting the RNA transcription level.

Identification of Rickettsia felis DNA in the blood of domestic cats and dogs in the USA

BackgroundThe main vector and reservoir host of Rickettsia felis, an emerging human pathogen causing flea-borne spotted fever, is the cat flea Ctenocephalides felis. While cats have not been found to be infected with the organism, significant percentages of dogs from Australia and Africa are infected, indicating that they may be important mammalian reservoirs. The objective of this study was to determine the presence of R. felis DNA in the blood of domestic dogs and cats in the USA.MethodsThree previously validated PCR assays for R. felis and DNA sequencing were performed on blood samples obtained from clinically ill domestic cats and dogs from 45 states (2008–2020) in the USA. The blood samples had been submitted for the diagnosis of various tick-borne diseases in dogs and feline infectious peritonitis virus, feline immunodeficiency virus, and Bartonella spp. in cats. Phylogenetic comparisons were performed on the gltA nucleotide sequences obtained in the study and those reported for R. felis and R. felis-like organisms.ResultsLow copy numbers of R. felis DNA (around 100 copies/ml whole blood) were found in four cats (4/752, 0.53%) and three dogs (3/777, 0.39%). The very low levels of infection in clinically ill animals is consistent with R. felis being an unlikely cause of disease in naturally infected dogs and cats. The low copy numbers we found emphasize the requirement for very sensitive PCRs in prevalence studies.ConclusionsThe low prevalence of naturally infected PCR-positive cats is further evidence that cats are unlikely to be important reservoirs of R. felis. Similarly, the low prevalence in dogs suggests they are not important reservoirs in the USA. Investigations should continue into the role other mammalian species may be playing in the epidemiology of R. felis infections. Graphical

Feline immunodeficiency virus (FIV) in sick cats in Sri Lanka; prevalence, diagnosis, and treatment

Feline Immunodeficiency virus (FIV) is a lent virus; significant pathogen in cats which causes a syndrome, with many similarities to Human Immunodeficiency Virus (HIV). The prevalence of disease is currently unknown in Sri Lanka as cage-side test kits for the viruses were not available until recently. This retrospective study evaluated 39 sick cats presented to Rover veterinary hospital since August 2018 till March 2019. They all shared a prior history of being bitten by another cat even though they were presented with different clinical signs. Out of 39, nine cats were positive for FIV anti body which was a share of 23 percent of the population selected. The diagnosis was confirmed by a commercially available ELISA test kit (Idexx SNAP FIV/FeLV Combo ®; IDEXX laboratories, USA); (FeLV-Feline Leukemia Virus). All the cats were treated for the related diseases along with the treatment for FIV. Lamuvudine was the drug of choice; a class of medications called nucleoside reverse transcriptase inhibitors (NRTIs) which act by decreasing the amount of viremia. The medication was continued for 3 months in each patient at a dose of 20 mg/kg bid and have stopped once the animal has become clinically normal. The prognosis was determined by the improvement of clinical signs, curing of chronic bacterial infections, improvement of full blood count, FIV/FeLV SNAP and by differential cell count with regards to the lymphoblast percentage reduction in blood smears. Out of the seven cats who recovered from the secondary infections, constipation and emaciation; blood smears were obtained while they were on Lamuvudine. A gradual reduction or no lymphoblast counts were observed in the blood smear of 4 cats over a period of three months during therapy. Seven cats recovered after the treatment while two cats were ceased. We attained a recovery rate of 77% in critically ill patients. FIV positivity was associated with a history of bite wounds, male gender. Related clinical signs are most often a reflection of opportunistic infections. Early diagnosis of FIV is important for successful treatment to regain the immunity, better survival rates and screening is essential to prevent the spread of the disease.

HIV-1 Gag Forms Ribonucleoprotein Complexes with Unspliced Viral RNA at Transcription Sites.

The ability of the retroviral Gag protein of Rous sarcoma virus (RSV) to transiently traffic through the nucleus is well-established and has been implicated in genomic RNA (gRNA) packaging Although other retroviral Gag proteins (human immunodeficiency virus type 1, HIV-1; feline immunodeficiency virus, FIV; Mason-Pfizer monkey virus, MPMV; mouse mammary tumor virus, MMTV; murine leukemia virus, MLV; and prototype foamy virus, PFV) have also been observed in the nucleus, little is known about what, if any, role nuclear trafficking plays in those viruses. In the case of HIV-1, the Gag protein interacts in nucleoli with the regulatory protein Rev, which facilitates nuclear export of gRNA. Based on the knowledge that RSV Gag forms viral ribonucleoprotein (RNPs) complexes with unspliced viral RNA (USvRNA) in the nucleus, we hypothesized that the interaction of HIV-1 Gag with Rev could be mediated through vRNA to form HIV-1 RNPs. Using inducible HIV-1 proviral constructs, we visualized HIV-1 Gag and USvRNA in discrete foci in the nuclei of HeLa cells by confocal microscopy. Two-dimensional co-localization and RNA-immunoprecipitation of fractionated cells revealed that interaction of nuclear HIV-1 Gag with USvRNA was specific. Interestingly, treatment of cells with transcription inhibitors reduced the number of HIV-1 Gag and USvRNA nuclear foci, yet resulted in an increase in the degree of Gag co-localization with USvRNA, suggesting that Gag accumulates on newly synthesized viral transcripts. Three-dimensional imaging analysis revealed that HIV-1 Gag localized to the perichromatin space and associated with USvRNA and Rev in a tripartite RNP complex. To examine a more biologically relevant cell, latently infected CD4+ T cells were treated with prostratin to stimulate NF-κB mediated transcription, demonstrating striking localization of full-length Gag at HIV-1 transcriptional burst site, which was labelled with USvRNA-specific riboprobes. In addition, smaller HIV-1 RNPs were observed in the nuclei of these cells. These data suggest that HIV-1 Gag binds to unspliced viral transcripts produced at the proviral integration site, forming vRNPs in the nucleus.

Investigation of the Structure and Dynamics of Antiviral Drug Adefovir Dipivoxil by Site-Specific Spin-Lattice Relaxation Time Measurements and Chemical Shift Anisotropy Tensor Measurements.

Adefovir is regarded as a potential antiviral agent. However, it cannot be considered as a valuable drug candidate due to its high polarity that limits its permeability across the human intestinal mucosa. When the ribose phosphate group of adefovir is replaced by the isopolar phosphonomethyl ether functionality, it neutralizes the negative charge of the drug. This makes the drug lipid-soluble and potent to diffuse across the cell membrane. The prodrug adefovir dipivoxil is regarded as a potent antiviral drug against hepatitis B virus (HBV), human immunodeficiency virus (HIV), Rauscher murine leukemia virus (R-MuLV), murine cytomegalovirus (MCMV), herpes simplex virus (HSV), simian immunodeficiency virus (SIV), and feline immunodeficiency virus (FIV). The correlation between the structure and the dynamics of adefovir dipivoxil is determined by measuring the principal components of chemical shift anisotropy (CSA) tensor, site-specific spin–lattice relaxation time, and molecular correlation time at crystallographically different carbon nuclei sites. The CSA parameters, spin–lattice relaxation time, and molecular correlation time of phosphorous nucleus of the organophosphate group of adefovir dipivoxil molecule are also determined. The spin–lattice relaxation time of carbon nuclei varies from 1 to 107 s. The range of molecular correlation time also varies from 10–4 to 10–8 s. These remarkable diversities of motional dynamics of the molecules imply that there exist various motional degrees of freedom within this valuable drug and these motional degrees of freedom are independent of each other, which may be the reason for the biological activities exhibited by the drug. The correlation between structure and dynamics of such an important antiviral drug adefovir dipivoxil can be visualized by these types of extensive spectroscopic measurements, which will enlighten the path of inventing advanced medicine in the pharmaceutical industry, and it will also illuminate the understanding of the structure–activity relationships of antiviral drug.

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Insights into the genetic diversity, recombination, and systemic infections with evidence of intracellular maturation of hepadnavirus in cats.

Hepatitis B virus (HBV) is a human pathogen of global concern, while a high diversity of viruses related to HBV have been discovered in other animals during the last decade. Recently, the novel mammalian hepadnavirus, tentatively named domestic cat hepadnavirus (DCH), was detected in an immunocompromised cat. Herein, a collection of 209 cat sera and 15 hepato-diseased cats were screened for DCH using PCR, resulting in 12.4% and 20% positivity in the tested sera and necropsied cats, respectively. Among the DCH-positive sera, a significantly high level of co-detection with retroviral infection was found, with the highest proportion being co-detection with feline immunodeficiency virus (FIV). Full-length genome characterization of DCH revealed the genetic diversity between the nine Thai DCH sequences obtained, and that they phylogenetically formed three distinct monophyletic clades. A putative DCH recombinant strain was found, suggesting a possible role of recombination in DCH evolution. Additionally, quantitative PCR was used to determine the viral copy number in various organs of the DCH-moribund cats, while the pathological findings were compared to the viral localization in hepatocytes, adjacent to areas of hepatic fibrosis, by immunohistochemical (IHC) and western blot analysis. In addition to the liver, positive-DCH immunoreactivity was found in various other organs, including kidneys, lung, heart, intestine, brain, and lymph nodes, providing evidence of systemic infection. Ultrastructure of infected cells revealed electron-dense particles in the nucleus and cytoplasm of hepatocytes, bronchial epithelial cells, and fibroblasts. We propose the intracellular development mechanism of this virus. Although the definitive roles of pathogenicity of DCH remains undetermined, a contributory role of the virus associated with systemic diseases is possible.

Detection of severe fever with thrombocytopenia syndrome virus and other viruses in cats via unbiased next-generation sequencing.

We used unbiased next-generation sequencing (NGS) to detect unknown viruses in cats. Serum or plasma samples were obtained from clinically ill cats with suspected acute viral infections. Nucleic acid was extracted from serum or plasma samples to construct a complementary DNA library for NGS. Comprehensive nucleotide sequencing analyses enabled detection of the genomes of various viruses, including the severe fever with thrombocytopenia syndrome virus, feline immunodeficiency virus, feline morbillivirus, parvovirus, and Torque teno felis virus. Our findings indicate that comprehensive nucleotide analyses of serum or plasma samples can be used to detect infections with unknown viruses in cats.

Identification of the nuclear and nucleolar localization signals of the Feline immunodeficiency virus Rev protein

Lentivirus genomes code for a regulatory protein essential for virus replication termed Rev. The Rev protein binds to partially spliced and unspliced viral RNAs and mediates their nuclear export. Therefore, Rev possesses functional domains that enable its shuttling between the cytoplasm and the nucleus. The Feline immunodeficiency virus (FIV), a lentivirus, can lead to an immunodeficiency syndrome after a long incubation period, similar to that associated with the human immunodeficiency virus type 1 (HIV-1). The FIV Rev functional domains have been predicted only by homology with those of HIV-1 Rev. In the present study, the nuclear and nucleolar localization signals (NLS and NoLS, respectively) of the FIV Rev were examined. A series of FIV Rev deletion mutants fused to the enhanced green fluorescent protein (EGFP) were used to localize the NLS in a region spanning amino acids (aa) 81–100. By using alanine substitution mutants, basic residues present between the amino acids (aa) 84–99 of the FIV Rev protein sequence were identified to form the NLS, whereas those between aa 82–95 were associated with the NoLS function. These results further enhance our understanding of how Rev exerts its role in the replication cycle of lentiviruses.

Presumptive coccygeal diskospondylitis in a cat

Veterinary Record Case ReportsVolume 8, Issue 4 e001262 Images In… Presumptive coccygeal diskospondylitis in a cat Theophanes Liatis, Corresponding Author Theophanes Liatis theofanis.liatis@gmail.com orcid.org/0000-0003-2815-2527 Neurology & Neurosurgery Service, Small Animal...

Detection and modeling of anti-Leptospira IgG prevalence in cats from Lisbon area and its correlation to retroviral infections, lifestyle, clinical and hematologic changes

Leptospirosis is a zoonosis of global importance caused by Leptospira species. Rodents are the main reservoirs, known to shed the bacteria in urine, thus contaminating water and soil and infecting other animals and people. Leptospirosis has been re-emerging in both developing and developed countries including Europe. It has been hypothesized that cats could be asymptomatic carriers of Leptospira. This study aims to evaluate cats’ exposure to Leptospira in Lisbon, Portugal, by measuring IgG titres and correlating them with possible factors that may increase the risk of exposure in urban cats. Two hundred and forty-three samples were collected from the biobank. An ELISA test followed by a seroprevalence analysis using a finite mixture model was performed to detect and measure anti-Leptospira IgG antibodies titres. In parallel, a survey was conducted to identify possible risk factors for seropositivity.According to the ELISA test protocol, only twenty-three cats (9.5%; 95% CI =(6.1%;13.9%)) could be considered as seropositive to Leptospira antigens. However, when the same data were analysed by the best different mixture models, one hundred and forty-four cats (59.3%; 95%CI = (52.8%; 65.5%)) could be classified as intermediate and high antibody responders to Leptospira antigens. Seropositivity to Feline Immunodeficiency Virus infection (FIV) was found to be the only significant risk factor associated with anti-Leptospira IgG antibodies. In conclusion, the present studies raises the possibility of a higher exposure of cats to Leptospira than previously thought due to the identification of a subpopulation of cats with intermediate antibody levels.

Lack of protection against feline immunodeficiency virus infection among domestic cats in New Zealand vaccinated with the Fel-O-Vax® FIV vaccine

Infections with feline immunodeficiency virus (FIV) are common in New Zealand, although the impact of those infections on the health status of the cats remains unclear. Although many cats are vaccinated yearly with a commercial FIV vaccine containing FIV subtypes A and D, the effectiveness of this vaccine in protection against infection with field FIVs is unclear, as a high proportion of New Zealand viruses belong to subtype C. The objective of the study was to compare the frequency of FIV infection among adult FIV-vaccinated and FIV-unvaccinated domestic cats with access to outdoors. Buccal swabs were collected by the participating veterinarians and tested for the presence of FIV provirus by quantitative PCR. Overall, 26/185 (14.0 %) samples were positive for FIV, including 7/82 (8.5 %) samples from FIV-unvaccinated and 19/103 (18.4 %) from FIV-vaccinated cats. There was no protective effect of vaccination on FIV infection among sampled cats (p = 0.05). Partial sequences of the FIV envelope gene from five New Zealand viruses were analysed by the maximum likelihood method. All clustered with other New Zealand FIV sequences from subtypes A (n = 2), C (n = 2) or putative recombinant viruses (n = 1). While the FIV vaccination did not prevent FIV infection among sampled cats, it may have had an impact on transmissibility of the virus or on disease progression. As neither was addressed in the current study, further research is needed to fully assess the potential benefits of FIV vaccination. Considering the frequency of FIV infection in FIV-vaccinated cats, FIV infection status should be monitored not only before the first vaccination, but before each yearly booster.

Linfoma multicéntrico en felino doméstico: Reporte de caso

Lymphomas are neoplasms characterized by the clonal proliferation of malignant lymphocytes, originating mainly from lymphoid organs, such as bone marrow, spleen and lymph nodes. According to human terminology, lymphomas that occur in domestic animals are known as non-Hodgkin, whose biological behavior, epidemiology, cell morphology and phenotyping are quite similar between humans and small animals. Lymphoma is the most common feline neoplasia, comprising more than 50% of all hemolymphatic tumors. The precise etiology of feline lymphoma is not known in many cases; however, viral causes are well defined, with infections by both feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV). When lymphoma is caused by FeLV, it is usually associated with progressive infection, but regressive infections can also be involved in tumor formation, whose virus is not detected by the ELISA test, but in PCR (peripheral blood or bone marrow) is found FeLV provirus DNA, this suggests that the virus may be associated with a higher proportion of lymphomas than expected. Such neoplasms can present in different anatomical locations being classified into multicentric, mediastinal (or thymic), alimentary and extranodal (cutaneous, nasal, renal and nervous system lymphoma). In cats, mediastinal and alimentary forms are more common than multicentric and extranodal forms. The present work aims to present the case report of a domestic feline, male, SRD, 1 year old and FIV / FeLV negative in the ELISA, showing an increase in peripheral lymph nodes (submandibular, inguinal and popliteal) and an increase in liver lymph nodes, pancreatoduodenal, medial, colic and mesenteric iliac. Submandibular lymph node cytology was performed where immunoblastic lymphoma was diagnosed. The patient was submitted to the CHOP chemotherapy protocol (Cyclophosphamide, Doxorubicin, Vincristine and Prednisolone) for 24 weeks, being discharged after this period.

A phylogenetic study of Feline Immunodeficiency Virus (FIV) among domestic cats in Turkey

Feline Immunodeficiency Virus (FIV) is the most prominent retrovirus in cats. Molecular studies on FIV are of great importance to enable further studies, for example, understanding the pathogenesis and developing improved vaccines. We aimed to elucidate the molecular status of FIV and provide a detailed characterization of FIV in Turkey because at present there is very limited information available in the literature. We also evaluated a potential link between clinical symptoms and FIV subtypes according to results obtained from molecular tests.Whole blood was collected from 200 client-owned domestic cats and molecular diagnosis and characterization was performed. The env, gag and vif gene regions were amplified and sequenced for phylogenetic analysis. We obtained specific amplicons based on bothenvand gag for FIV in 21 cats; only 2 of the 21 positive samples could also be characterized based on the vif gene region. Separate clusters were identified according to previously determined genotyping strategies; however, they were observed in FIV subtype B. The molecular findings of some individual cats were evaluated in conjunction with their clinical symptoms in an attempt to determine potential relationships between the genetic characteristics of FIV and symptoms of disease. As a result, overexpression of the vif gene could be important in leading to serious clinical symptoms.Our results emphasize the necessity of considering FIV in diagnosis and performing the neccesary diagnostics to confirm or rule out FIV infection. The molecular dynamics of FIV should be periodically updated by further analyses to establish a successful prevention strategy.

Successful Management of Immune-Mediated Hemolytic Anemia Secondary to Infection with Cytauxzoon felis and Feline Immunodeficiency Virus

Successful Management of Immune-Mediated Hemolytic Anemia Secondary to Infection with Cytauxzoon felis and Feline Immunodeficiency Virus

Disseminated histoplasmosis with ocular adnexal involvement in seven cats

To describe the clinical features, diagnosis, and treatment of disseminated histoplasmosis with conjunctival and/or nictitating membrane involvement in cats. Medical records from seven cats with naturally acquired disseminated histoplasmosis and conjunctival and/or nictitating membrane lesions were reviewed for signalment, clinical findings, diagnostic results, treatment, and outcome. Breeds included domestic shorthair (n=5), Maine Coon (n=1), and Siamese mix (n=1) with four spayed females and three castrated males. Conjunctival abnormalities were identified in four cats, and nictitating membrane lesions were identified in four cats; one cat had both a conjunctival and nictitating membrane lesion. Cytologic evaluation of lesions identified Histoplasma capsulatum organisms in two of four cases sampled, and histopathologic evaluation identified Hcapsulatum in both cases in which a sample was submitted. Histoplasmosis antigen testing was positive in three of four submitted samples. Initial treatment for all cats included fluconazole (median dose: 26mg/kg/d). Median duration of follow-up was 11months (range: 1-108months; n=4). Resolution of ocular adnexal lesions was achieved in three cats. Two cats had relapse of disease, one of which was subsequently euthanized. One cat with concurrent feline immunodeficiency virus (FIV) infection died one month after diagnosis of histoplasmosis. Histoplasmosis should be a differential diagnosis for ocular adnexal inflammatory lesions in cats.

Clinical and Hematological Follow-Up of Long-Term Oral Therapy with Type-I Interferon in Cats Naturally Infected with Feline Leukemia Virus or Feline Immunodeficiency Virus.

Simple SummaryThe viruses which produce feline leukemia (FeLV) and feline immunodeficiency (FIV) attack cells involved in the immune response. As specific drugs are either nonexistent, produce secondary effects, or are expensive, a therapeutic possibility is using nonspecific immunostimulants, such as human interferon alpha. We used this drug to treat 27 cats infected by FeLV and 31 infected by FIV. All cats were naturally infected and treatment was administered orally by their owners for four months. Participating cats were evaluated in our clinics at mid-treatment (M2), end of treatment (M4), and 4–8 months after the end of treatment (M10). We observed that treatment was well tolerated by the cats (as it did not affect the liver or the kidney functions), and improved most of the parameters analyzed (clinic, anemia, white cell counts, and CD4+/CD8+ ratio) as long as it was administered. However, 4–8 months after it was discontinued, though most animals remained clinically healthy, many of these parameters had rebounded to initial values or values even worse than the initial values. Thus, more studies should be conducted with longer administration of this drug to evaluate tolerability and sustained improvement of diseases produced by these two viruses which may lead to death.Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV), two of the most important pathogens of cats, produce chronic systemic diseases with progressive death of cells involved in the immune response, ultimately leading to death. Immunostimulants is one of the few alternatives to the symptomatic treatment. In this study, 27 naturally FeLV-infected (FeLV+) and 31 naturally FIV-infected (FIV+) cats were administered orally by their owners 60 IU/day of recombinant human interferon alpha (rHuIFN-α) for four months in alternate weeks. Clinical status was evaluated and blood samples collected at four different visits or months (M): pretreatment (M0), mid-treatment (M2), end of treatment (M4), and 4–8 months after end of treatment (M10). Most cats ostensibly improved their clinical status, and many became asymptomatic. rHuIFN-α treatment improved the anemic processes observed at M0 (at least in cats with mild or moderate anemia) and leukocyte counts, including a more favorable CD4+/CD8+ ratio. An increase in the serum gammaglobulin concentration was seen in 80% of the cats. Despite observing an obvious favorable progress in the clinical, biopathological, and CD4+/CD8+ values during treatment, almost invariably all the parameters analyzed worsened after treatment discontinuation (M10), which suggests that the interferon-α protocol should be either extended or include additional cycles for a long-lasting benefit in FeLV+ and FIV+ cats.