Experimental infection of BALB/c mice with felid alphaherpesvirus 1 / Infecção experimental de camundongos BALB/c com alphaherpesvírus felino tipo 1

Felid alphaherpesvirus type 1 (FHV-1) is an important cause of respiratory and ocular diseases in cats worldwide. Mice have been widely used to study the pathogenesis of several human and animal viruses, especially herpesviruses. This study aimed to verify whether BALB/c mice are susceptible to FHV-1 infection. The animals were intranasally inoculated with FHV-1 and their clinical signs were observed from 3 days postinfection (dpi). At 10 dpi, the animals were euthanized and the lungs, liver, spleen, and kidneys were collected for histopathological examination and quantitative polymerase chain reaction. The results showed that mice were infected with FHV-1 and reproduced several features of the disease observed in its natural host. Histological lesions and viral DNA were found in all sampled tissues, with a higher frequency of FHV-1 DNA copies detected in the lungs. All mice were seroconverted to FHV-1 at 7 dpi. To our knowledge, this is the first report of experimental infection of BALB/c mice with FHV-1. Our findings demonstrate that this murine model can contribute to understanding of FHV-1 pathogenesis and may be useful for trials against this virus.(AU)

O herpesvírus felino tipo 1 (FHV-1) é um importante agente causador de doença respiratória e ocular em gatos em todo o mundo. Camundongos têm sido amplamente utilizados para estudar a patogenia de diversos vírus humanos e animais, especialmente os herpesvírus. O objetivo deste estudo foi verificar se camundongos BALB/c poderiam ser suscetíveis a infecção pelo FHV-1. Os animais foram inoculados com FHV-1 intranasalmente e sinais clínicos foram observados a partir do dia 3 após a infecção (dpi). Após dez dias da inoculação, os animais foram eutanasiados e os pulmões, fígado, baço e rins foram coletados para exame histopatológico e PCR quantitativo (qPCR). Os resultados mostraram que os camundongos foram infectados com o FHV-1 e reproduziram várias características da doença que são observadas em seu hospedeiro natural. Lesões histológicas e DNA viral foram detectadas em todos os tecidos amostrados, com maior frequência de DNA do FHV-1 nos pulmões. Todos os camundongos soroconverteram para FHV-1 aos 7 dpi. Para nosso conhecimento, este estudo é o primeiro relato de infecção experimental de camundongos BALB/c com FHV-1. Nossos resultados demonstraram que esse camundongo pode contribuir para o entendimento da patogenia do FHV-1 e pode ser um modelo útil para ensaios contra esse vírus.(AU)

Feline herpesvirus 1 viral load related to environmental factors in sheltered cats / Relação entre carga viral de herpesvirus felino 1 e fatores causadores de estresse em felinos de abrigo

Shelter environment stress factors are related to FHV-1 viral reactivation. However, comparisons between conjunctival viral load and environmental factors have not been commonly evaluated. The aim of this study was to correlate FHV-1 viral load in domestic cats with and without clinical signs of conjunctivitis to shelter design in order to use FHV-1 viral load as a parameter of “health management”. Cats from four different shelters underwent an ophthalmological examination. Samples were collected by rolling a DNA/RNAse-free cytobrush over the ventral conjunctival fornix and were stored in 1.5 mL sterile microtubes in 500 μL of Eagles minimum essential medium and kept at 4 ºC. Molecular procedures were performed up to 48 hours after collection. Different routines regarding new arrivals were directly related to FHV-1 viral load. Shelters where new arrivals occurred on daily basis had the highest viral load (2.69x108 copies/µL), while those shelters where new arrivals had not occurred in the few months prior to the beginning of the study had the lowest rate (1.63x103 copies/µL). Environmental factors directly influenced FHV-1 DNA viral load. This study highlighted the need to improve the management approach in the animal shelter environment to reduce stressful situations responsible for FHV-1 reactivation and higher viral load quantification.(AU)

No ambiente do abrigo encontram-se fatores que geram estresse nos animais que ali residem. Esses fatores acabam por provocar a reativação do FHV-1. No entanto, comparações entre carga viral conjuntival e fatores ambientais não foram ainda avaliadas. Objetivo deste estudo foi correlacionar a carga viral de FHV-1 em felinos domésticos com e sem sinais clínicos de conjuntivite com as características dos abrigos. Assim, pode-se usar carga viral de FHV-1 como parâmetro de sanidade. Todos os gatos foram submetidos a exame clínico oftalmológico. Amostras foram coletadas com uso de escova citológica, acondicionadas em microtubos estéreis de 1,5mL contendo 500 μL de meio Eagle essencial mínimo e mantidas em 4 ºC. Análises moleculares foram realizadas no prazo de 48 horas após coleta. A rotina de entrada de novos animais estava diretamente relacionada a carga viral de FHV-1. Abrigos com entrada diária apresentaram carga viral maior (2.69x108 cópias/µL), do que abrigo onde novos animais não chegaram nos meses que antecederam a coleta (1.63x103 cópias/µL). Fatores ambientais influenciam diretamente carga viral de FHV-1. Esse estudo evidencia a necessidade de aprimorar o sistema de manejo dos abrigos de forma a reduzir situações de estresse responsáveis pela reativação de FHV-1 e consequente aumento na carga viral.(AU)

Feline herpesvirus 1 viral load related to environmental factors in sheltered cats / Relação entre carga viral de herpesvirus felino 1 e fatores causadores de estresse em felinos de abrigo

ABSTRACT: Shelter environment stress factors are related to FHV-1 viral reactivation. However, comparisons between conjunctival viral load and environmental factors have not been commonly evaluated. The aim of this study was to correlate FHV-1 viral load in domestic cats with and without clinical signs of conjunctivitis to shelter design in order to use FHV-1 viral load as a parameter of "health management". Cats from four different shelters underwent an ophthalmological examination. Samples were collected by rolling a DNA/RNAse-free cytobrush over the ventral conjunctival fornix and were stored in 1.5 mL sterile microtubes in 500 μL of Eagle's minimum essential medium and kept at 4 ºC. Molecular procedures were performed up to 48 hours after collection. Different routines regarding new arrivals were directly related to FHV-1 viral load. Shelters where new arrivals occurred on daily basis had the highest viral load (2.69x108 copies/µL), while those shelters where new arrivals had not occurred in the few months prior to the beginning of the study had the lowest rate (1.63x103 copies/µL). Environmental factors directly influenced FHV-1 DNA viral load. This study highlighted the need to improve the management approach in the animal shelter environment to reduce stressful situations responsible for FHV-1 reactivation and higher viral load quantification.

RESUMO: No ambiente do abrigo encontram-se fatores que geram estresse nos animais que ali residem. Esses fatores acabam por provocar a reativação do FHV-1. No entanto, comparações entre carga viral conjuntival e fatores ambientais não foram ainda avaliadas. Objetivo deste estudo foi correlacionar a carga viral de FHV-1 em felinos domésticos com e sem sinais clínicos de conjuntivite com as características dos abrigos. Assim, pode-se usar carga viral de FHV-1 como parâmetro de sanidade. Todos os gatos foram submetidos a exame clínico oftalmológico. Amostras foram coletadas com uso de escova citológica, acondicionadas em microtubos estéreis de 1,5mL contendo 500 μL de meio Eagle essencial mínimo e mantidas em 4 ºC. Análises moleculares foram realizadas no prazo de 48 horas após coleta. A rotina de entrada de novos animais estava diretamente relacionada a carga viral de FHV-1. Abrigos com entrada diária apresentaram carga viral maior (2.69x108 cópias/µL), do que abrigo onde novos animais não chegaram nos meses que antecederam a coleta (1.63x103 cópias/µL). Fatores ambientais influenciam diretamente carga viral de FHV-1. Esse estudo evidencia a necessidade de aprimorar o sistema de manejo dos abrigos de forma a reduzir situações de estresse responsáveis pela reativação de FHV-1 e consequente aumento na carga viral.

Effect of a Pheromone on Stress-Associated Reactivation of Feline Herpesvirus-1 in Experimentally Inoculated Kittens.

BACKGROUND: Stress contributes to reactivation of feline herpesvirus-1 (FHV-1). The usage of pheromones to decrease stress in FHV-1 experimentally inoculated kittens has not previously been investigated. HYPOTHESIS/OBJECTIVES: To determine whether a feline pheromone would lessen stress, resulting in decreased recurrence of FHV-1-associated illness in kittens. ANIMALS: Twelve 5-month-old, purpose-bred kittens. METHODS: Randomized, double-blind, placebo-controlled clinical trial. Kittens previously infected with the same dose of FHV-1 were randomized into 2 separate but identical group rooms. After a 2-week equilibration period, a diffuser containing either the pheromone or placebo was placed in each of the rooms, and the kittens acclimated for an additional 2 weeks. Every 2 weeks thereafter, for the 8-week study period, housing was alternated between kennel- and group housing. Blinded observers applied a standardized clinical and behavioral scoring rubric daily. After each 2-week period, serum cortisol concentrations and quantitative PCR for FHV-1 and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) ratios were evaluated. Clinical, behavioral, and laboratory test results were compared between groups within individual and combined study periods. RESULTS: Sneezing occurred more frequently in the placebo group during individual (P = 0.006) and combined study periods (P = 0.001). Sleep at the end of observation periods occurred more frequently in the pheromone group during individual (P = 0.006) and combined study periods (P < 0.001). CONCLUSIONS AND CLINICAL IMPORTANCE: The findings suggest that the pheromone decreased stress, and the decrease in stress response may have resulted in decreased sneezing associated with FHV-1.

Detecção de Herpesvírus Felino do tipo 1 e Chlamydia felis em gatil de superpopulação em São Paulo / Detection of Herpesvirus Feline type 1 and Chlamydia telis in thecattery of overpopulation in São Paulo city / Deteccion de Herpesvirus Felino tipo 1 y Chlamydia telis en un criaderocon sobrepoblación en la ciudad deSão Paulo

Dentre os principais agentes causadores do complexo respiratório dos felinos tem-se o Herpesvírus felino tipo 1 (FHV-1) e a Chlamydia telis. Esta é a principal enfermidade causadora de surtos em abrigos de felinos. Avaliou-se 39 felinos de uma população oscilante em torno de 200 indivíduos, encontrou-se alta ocorrência tanto de FHV-1 como de C. telis. Dentre os fatores de risco que favoreciam a propagação da infecção,foram detectados as baixas condições sanitárias e nutricionais oferecida aos animais. Todos animais do estudo não possuíam raça definida e eram provenientes de resgate de vias públicas, 100% dos animais deste gatil apresentava sinais clínicos do complexo respiratório dos felinos e tanto a morbidade quanto a mortalidade eram elevadas.(AU)

Among the main causes of respiratory complex feline has Herpesvirus feline type 1 (FHV-1)and Chlamydia telis. This is the main disease causing outbreaks in felines shelters. It was evaluated 39 cats from an oscillating population of around 200 individuais, it was found a high rate of both FHV-1 asC. telis. Risk factors favoring the spread of infection were low health and nutritional conditions offered to animais. Ali animais in the study lacked breed and came from rescue roads, 100% of the animais of this cattery presented clinical signs of respiratory complex feline and both morbidity and mortality were high.(AU)

Entre los principales patógenos que causan el complejo respiratorio felino se encuentran el Herpesvirus felino tipo 1 (FHV-1) y la Chlamydia telis. Esta es la principal enfermedad que causa brotes en refugios de felinos, por tanto, en este trabajo fueron evaluados 39 gatos de una población de aproximadamente 200 individuos, encontrán dose una alta ocurrencia de FHV-1 y C. telis. Los factores de riesgo que favorecieron a la propagación de la infección fueron las bajas condiciones sanitarias y nutricionales de los animales. Todos los individuos de este criadero fueron rescatados de las vías públicas, eran de raza desconocida, presentaban signos clínicos dei complejo respiratorio felino y una alta tasa de morbilidad y mortalidad.(AU)

Detecção de Herpesvírus Felino do tipo 1 e Chlamydia felis em gatil de superpopulação em São Paulo / Detection of Herpesvirus Feline type 1 and Chlamydia telis in thecattery of overpopulation in São Paulo city / Deteccion de Herpesvirus Felino tipo 1 y Chlamydia telis en un criaderocon sobrepoblación en la ciudad deSão Paulo

Dentre os principais agentes causadores do complexo respiratório dos felinos tem-se o Herpesvírus felino tipo 1 (FHV-1) e a Chlamydia telis. Esta é a principal enfermidade causadora de surtos em abrigos de felinos. Avaliou-se 39 felinos de uma população oscilante em torno de 200 indivíduos, encontrou-se alta ocorrência tanto de FHV-1 como de C. telis. Dentre os fatores de risco que favoreciam a propagação da infecção,foram detectados as baixas condições sanitárias e nutricionais oferecida aos animais. Todos animais do estudo não possuíam raça definida e eram provenientes de resgate de vias públicas, 100% dos animais deste gatil apresentava sinais clínicos do complexo respiratório dos felinos e tanto a morbidade quanto a mortalidade eram elevadas.

Among the main causes of respiratory complex feline has Herpesvirus feline type 1 (FHV-1)and Chlamydia telis. This is the main disease causing outbreaks in felines shelters. It was evaluated 39 cats from an oscillating population of around 200 individuais, it was found a high rate of both FHV-1 asC. telis. Risk factors favoring the spread of infection were low health and nutritional conditions offered to animais. Ali animais in the study lacked breed and came from rescue roads, 100% of the animais of this cattery presented clinical signs of respiratory complex feline and both morbidity and mortality were high.

Entre los principales patógenos que causan el complejo respiratorio felino se encuentran el Herpesvirus felino tipo 1 (FHV-1) y la Chlamydia telis. Esta es la principal enfermedad que causa brotes en refugios de felinos, por tanto, en este trabajo fueron evaluados 39 gatos de una población de aproximadamente 200 individuos, encontrán dose una alta ocurrencia de FHV-1 y C. telis. Los factores de riesgo que favorecieron a la propagación de la infección fueron las bajas condiciones sanitarias y nutricionales de los animales. Todos los individuos de este criadero fueron rescatados de las vías públicas, eran de raza desconocida, presentaban signos clínicos dei complejo respiratorio felino y una alta tasa de morbilidad y mortalidad.

Isolation and identification of feline calicivirus and feline herpesvirus in Southern Brazil

Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the two primary causes of upper respiratory tract disease in cats. The aim of this study was to demonstrate the distribution of FCV and FHV-1 among the feline population of several counties in Rio Grande do Sul State, Brazil. To this end, conjunctival and nasal swabs were collected from 302 cats from different locations, including households, breeding catteries, veterinary clinics, animal hospitals and experimental research facilities. The samples were collected between July 2006 to June 2009. The virus isolation was performed in CRFK cells and, subsequently, the identification was confirmed by PCR. FCV, FHV-1, or both were isolated from 55 cats from 28 different locations. FCV alone was isolated from 52.7% (29/55) of the animals that tested positively, FHV-1 alone was isolated from 38.2% (21/55) of the animals that tested positively, and co-infection were detected in 9.1% (5/55) of the animals that tested positively. Virus detection was more prevalent in cats that were less than 1 year old, among animals that shared a living space with other cats, and females. FCV and FHV-1 were isolated from vaccinated cats. In addition, both viruses were isolated from cats that showed no signs of disease. The results suggest that a carrier state is common for both viruses in the evaluated population. A search for other causes of respiratory disease in that population is necessary; and further studies relating to the molecular characterization of viruses and vaccine efficacy are also necessary.

Isolation and identification of feline calicivirus and feline herpesvirus in Southern Brazil.

Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the two primary causes of upper respiratory tract disease in cats. The aim of this study was to demonstrate the distribution of FCV and FHV-1 among the feline population of several counties in Rio Grande do Sul State, Brazil. To this end, conjunctival and nasal swabs were collected from 302 cats from different locations, including households, breeding catteries, veterinary clinics, animal hospitals and experimental research facilities. The samples were collected between July 2006 to June 2009. The virus isolation was performed in CRFK cells and, subsequently, the identification was confirmed by PCR. FCV, FHV-1, or both were isolated from 55 cats from 28 different locations. FCV alone was isolated from 52.7% (29/55) of the animals that tested positively, FHV-1 alone was isolated from 38.2% (21/55) of the animals that tested positively, and co-infection were detected in 9.1% (5/55) of the animals that tested positively. Virus detection was more prevalent in cats that were less than 1 year old, among animals that shared a living space with other cats, and females. FCV and FHV-1 were isolated from vaccinated cats. In addition, both viruses were isolated from cats that showed no signs of disease. The results suggest that a carrier state is common for both viruses in the evaluated population. A search for other causes of respiratory disease in that population is necessary; and further studies relating to the molecular characterization of viruses and vaccine efficacy are also necessary.

Isolation and identification of feline calicivirus and feline herpesvirus in Southern Brazil

Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the two primary causes of upper respiratory tract disease in cats. The aim of this study was to demonstrate the distribution of FCV and FHV-1 among the feline population of several counties in Rio Grande do Sul State, Brazil. To this end, conjunctival and nasal swabs were collected from 302 cats from different locations, including households, breeding catteries, veterinary clinics, animal hospitals and experimental research facilities. The samples were collected between July 2006 to June 2009. The virus isolation was performed in CRFK cells and, subsequently, the identification was confirmed by PCR. FCV, FHV-1, or both were isolated from 55 cats from 28 different locations. FCV alone was isolated from 52.7% (29/55) of the animals that tested positively, FHV-1 alone was isolated from 38.2% (21/55) of the animals that tested positively, and co-infection were detected in 9.1% (5/55) of the animals that tested positively. Virus detection was more prevalent in cats that were less than 1 year old, among animals that shared a living space with other cats, and females. FCV and FHV-1 were isolated from vaccinated cats. In addition, both viruses were isolated from cats that showed no signs of disease. The results suggest that a carrier state is common for both viruses in the evaluated population. A search for other causes of respiratory disease in that population is necessary; and further studies relating to the molecular characterization of viruses and vaccine efficacy are also necessary.