FeLV and lymphoma in Germany

Meichner K, Kruse BD, Hirschberger J and Hartmann K. Changes in prevalence of progressive feline leukaemia virus infection in cats with lymphoma in Germany. Vet Rec. 2012; 171: 348. 

Lymphoma is the most common feline cancer, comprising more than half of all hemolymphatic (blood and lymph system) tumors. Feline leukemia virus (FeLV) is a type of virus known to cause cancer (oncogenic retrovirus) and FeLV infection is a known risk factor for lymphoma development. In the past, FeLV infection accounted for the majority of cats that developed lymphoma. However, in the past 20 years, various reports suggest that a shift away from FeLV-associated tumor development has occurred once FeLV screening and vaccination became more commonplace.
 
FeLV infection outcome has also been recently reclassified into four categories (progressive, regressive, abortive, focal). Progressively infected cats have persistent antigenemia (viral antigen in the blood), high proviral load, and a median survival time of 2.4 years. The purpose of this large retrospective study, which included 390 client-owned cats, was to compare the incidence of cats with lymphoma and progressive FeLV infection in southern Germany between two time periods; namely, an early period between 1980 and 1994, and a later period between 1995 and 2009.  Age distribution and other differences in FeLV antigen-positive and FeLV antigen-negative cats with lymphoma were also assessed. 

Incidence of progressive FeLV infection in cats with lymphoma significantly decreased from 59% to 13% between the two time periods, consistent with other recent studies worldwide. During the earlier period, young to middle-aged cats (median 7 years) were likely to have lymphoma while during the later period mostly older cats (median 11 years) were diagnosed with lymphoma. Decreased prevalence of progressive FeLV infection likely contributed to this change in age distribution. Mediastinal lymphoma was uncommon (10% of cases), but half of these cats tested positive for FeLV antigen. 

FeLV-antigen negative cats with lymphoma that responded to chemotherapy showed significantly longer remission duration (472 days) than FeLV antigen–positive cats (25 days); however, survival time was not significantly affected (25 days versus 27 days). This incongruity was likely due to the high percentage of non-responders (74%) to chemotherapy among FeLV antigen-negative cats in the present study. The retrospective nature of this study over a 30-year period and the lack of chemotherapy standardization could account for high percentage of non-responders. In conclusions, this is the first study over such a long period of time that evaluated cats with lymphoma and assessed their association with progressive FeLV infection. [GO]

See also: Englert T, Lutz H, Sauter-Louis C and Hartmann K. Survey of the feline leukemia virus infection status of cats in Southern Germany. J Feline Med Surg. 2012; 14: 392-8. 

Related blog posts:
FeLV and FIV in Germany (Feb 2010)
Treatment of cats with FeLV or FIV (July 2012)

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Join us on Google+

Meichner K, Kruse BD, Hirschberger J and Hartmann K. Changes in prevalence of progressive feline leukaemia virus infection in cats with lymphoma in Germany. Vet Rec. 2012; 171: 348. 

Lymphoma is the most common feline cancer, comprising more than half of all hemolymphatic (blood and lymph system) tumors. Feline leukemia virus (FeLV) is a type of virus known to cause cancer (oncogenic retrovirus) and FeLV infection is a known risk factor for lymphoma development. In the past, FeLV infection accounted for the majority of cats that developed lymphoma. However, in the past 20 years, various reports suggest that a shift away from FeLV-associated tumor development has occurred once FeLV screening and vaccination became more commonplace.
 
FeLV infection outcome has also been recently reclassified into four categories (progressive, regressive, abortive, focal). Progressively infected cats have persistent antigenemia (viral antigen in the blood), high proviral load, and a median survival time of 2.4 years. The purpose of this large retrospective study, which included 390 client-owned cats, was to compare the incidence of cats with lymphoma and progressive FeLV infection in southern Germany between two time periods; namely, an early period between 1980 and 1994, and a later period between 1995 and 2009.  Age distribution and other differences in FeLV antigen-positive and FeLV antigen-negative cats with lymphoma were also assessed. 

Incidence of progressive FeLV infection in cats with lymphoma significantly decreased from 59% to 13% between the two time periods, consistent with other recent studies worldwide. During the earlier period, young to middle-aged cats (median 7 years) were likely to have lymphoma while during the later period mostly older cats (median 11 years) were diagnosed with lymphoma. Decreased prevalence of progressive FeLV infection likely contributed to this change in age distribution. Mediastinal lymphoma was uncommon (10% of cases), but half of these cats tested positive for FeLV antigen. 

FeLV-antigen negative cats with lymphoma that responded to chemotherapy showed significantly longer remission duration (472 days) than FeLV antigen–positive cats (25 days); however, survival time was not significantly affected (25 days versus 27 days). This incongruity was likely due to the high percentage of non-responders (74%) to chemotherapy among FeLV antigen-negative cats in the present study. The retrospective nature of this study over a 30-year period and the lack of chemotherapy standardization could account for high percentage of non-responders. In conclusions, this is the first study over such a long period of time that evaluated cats with lymphoma and assessed their association with progressive FeLV infection. [GO]

See also: Englert T, Lutz H, Sauter-Louis C and Hartmann K. Survey of the feline leukemia virus infection status of cats in Southern Germany. J Feline Med Surg. 2012; 14: 392-8. 

Related blog posts:
FeLV and FIV in Germany (Feb 2010)
Treatment of cats with FeLV or FIV (July 2012)

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Join us on Google+

Read More

Geographic variation in FeLV and FIV in the U.S.

Chhetri B, Berke O, Pearl D and Bienzle D. Comparison of the geographical distribution of feline immunodeficiency virus and feline leukemia virus infections in the United States of America (2000--2011). BMC Veterinary Research. 2013; 9: 2. [free, full text article] 
 
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) share many risk factors for infection in cats. However, infection rates are thought to vary depending on location. Geographical distribution of each may vary. These investigators looked at the geographical distribution of both viruses in the U.S. Testing results for over 17,000 (FIV) and 30,000 (FeLV) cats were analyzed for the 48 contiguous states. The results indicate that risk factors may vary in different geographic locales. There is a higher prevalence of FIV in the southeastern U.S. compared with FeLV. In contrast, FeLV occurred at a higher rate in the western U.S. compared with FIV. This may be due to geographic variations in virus strains, vaccination rates, or as yet unknown geographic risk factors for each virus. While more research is needed to understand the specific risk factors responsible, this knowledge could influence recommendations for testing, management, and prevention. [MK]

See also:
Levy J, Crawford C, Hartmann K, et al. 2008 American Association of Feline Practitioners' feline retrovirus management guidelines. J Feline Med Surg. 2008; 10: 300-16. [free, full text]

Little S, Bienzle D, Carioto L, Chisholm H, O'Brien E and Scherk M. Feline leukemia virus and feline immunodeficiency virus in Canada: recommendations for testing and management. Can Vet J. 2011; 52: 849-55. [free, full text] 

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Join us on Google+

Chhetri B, Berke O, Pearl D and Bienzle D. Comparison of the geographical distribution of feline immunodeficiency virus and feline leukemia virus infections in the United States of America (2000--2011). BMC Veterinary Research. 2013; 9: 2. [free, full text article] 
 
Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) share many risk factors for infection in cats. However, infection rates are thought to vary depending on location. Geographical distribution of each may vary. These investigators looked at the geographical distribution of both viruses in the U.S. Testing results for over 17,000 (FIV) and 30,000 (FeLV) cats were analyzed for the 48 contiguous states. The results indicate that risk factors may vary in different geographic locales. There is a higher prevalence of FIV in the southeastern U.S. compared with FeLV. In contrast, FeLV occurred at a higher rate in the western U.S. compared with FIV. This may be due to geographic variations in virus strains, vaccination rates, or as yet unknown geographic risk factors for each virus. While more research is needed to understand the specific risk factors responsible, this knowledge could influence recommendations for testing, management, and prevention. [MK]

See also:
Levy J, Crawford C, Hartmann K, et al. 2008 American Association of Feline Practitioners' feline retrovirus management guidelines. J Feline Med Surg. 2008; 10: 300-16. [free, full text]

Little S, Bienzle D, Carioto L, Chisholm H, O'Brien E and Scherk M. Feline leukemia virus and feline immunodeficiency virus in Canada: recommendations for testing and management. Can Vet J. 2011; 52: 849-55. [free, full text] 

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Join us on Google+

Read More

Treatment of cats with FeLV or FIV

Doménech A, Miró G, Collado VM et al: Use of recombinant interferon omega in feline retrovirosis: From theory to practice, Vet Immunol Immunopathol 143:301, 2011.
 
The feline retrovirus infections – feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) - cause lifelong infections often with chronic disease. To date, treatment has been primarily symptomatic and supportive. These investigators examined the usefulness of interferon as a more specific treatment. Interferon is a protein in the blood that can modify the immune response and that has antiviral capabilities. Interferon-omega is a type of interferon found in cats that has been cloned and synthesized and is commercially available in some countries. Clinical improvement was observed when interferon-omega was used to treat 11 cats with FeLV or FIV. Certain blood parameters, such as amount of red blood cells, also improved. While no antiviral effects were seen, the improved clinical condition of the infected cats support the use of interferon-omega in treating retrovirus-infected cats. [MK]

See also: de Mari K, Maynard L, Sanquer A et al: Therapeutic effects of recombinant feline interferon-omega on feline leukemia virus (FeLV)-infected and FeLV/feline immunodeficiency virus (FIV)-coinfected symptomatic cats, J Vet Intern Med 18:477, 2004.

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Read the Cat Health News Weekly
Join us on Google+

Doménech A, Miró G, Collado VM et al: Use of recombinant interferon omega in feline retrovirosis: From theory to practice, Vet Immunol Immunopathol 143:301, 2011.
 
The feline retrovirus infections – feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) - cause lifelong infections often with chronic disease. To date, treatment has been primarily symptomatic and supportive. These investigators examined the usefulness of interferon as a more specific treatment. Interferon is a protein in the blood that can modify the immune response and that has antiviral capabilities. Interferon-omega is a type of interferon found in cats that has been cloned and synthesized and is commercially available in some countries. Clinical improvement was observed when interferon-omega was used to treat 11 cats with FeLV or FIV. Certain blood parameters, such as amount of red blood cells, also improved. While no antiviral effects were seen, the improved clinical condition of the infected cats support the use of interferon-omega in treating retrovirus-infected cats. [MK]

See also: de Mari K, Maynard L, Sanquer A et al: Therapeutic effects of recombinant feline interferon-omega on feline leukemia virus (FeLV)-infected and FeLV/feline immunodeficiency virus (FIV)-coinfected symptomatic cats, J Vet Intern Med 18:477, 2004.

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter
Read the Cat Health News Weekly
Join us on Google+

Read More

Treatment for feline leukemia virus

Cattori V, Weibel B and Lutz H. Inhibition of feline leukemia virus replication by the integrase inhibitor raltegravir. Vet Microbiol. 2011; 152: 165-8.

Feline leukemia virus is a retrovirus of cats that can cause cancer, anemia and immunosuppression. Currently, no effective treatment for FeLV infection exists. These researchers investigated the usefulness of an anti-retroviral drug called raltegrevir that was developed for treatment of HIV in humans. The researchers tested the drug in a laboratory setting for potential toxicity to feline cells, as well as the ability to inhibit the replication of FeLV in these cells. It was found that, at least in cell culture, this drug inhibited virus replication and did not cause toxic changes to the feline cells. The researchers speculate that this drug could be used to reduce virus replication in FeLV-infected cats to the point that their own immune system could eliminate the virus, effectively curing the infection. Many more studies are needed, but this research offers a promising first step. [MK]

Related articles:
Hartmann K. Clinical aspects of feline immunodeficiency and feline leukemia virus infection. Vet Immunol Immunopathol. 2011; 143: 190-201.

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter

Cattori V, Weibel B and Lutz H. Inhibition of feline leukemia virus replication by the integrase inhibitor raltegravir. Vet Microbiol. 2011; 152: 165-8.

Feline leukemia virus is a retrovirus of cats that can cause cancer, anemia and immunosuppression. Currently, no effective treatment for FeLV infection exists. These researchers investigated the usefulness of an anti-retroviral drug called raltegrevir that was developed for treatment of HIV in humans. The researchers tested the drug in a laboratory setting for potential toxicity to feline cells, as well as the ability to inhibit the replication of FeLV in these cells. It was found that, at least in cell culture, this drug inhibited virus replication and did not cause toxic changes to the feline cells. The researchers speculate that this drug could be used to reduce virus replication in FeLV-infected cats to the point that their own immune system could eliminate the virus, effectively curing the infection. Many more studies are needed, but this research offers a promising first step. [MK]

Related articles:
Hartmann K. Clinical aspects of feline immunodeficiency and feline leukemia virus infection. Vet Immunol Immunopathol. 2011; 143: 190-201.

More on cat health:
Winn Feline Foundation Library
Find us on Facebook
Follow us on Twitter

Read More

Cats and Viruses

Hellard E, Fouchet D, Santin-Janin H et al: When cats' ways of life interact with their viruses: a study in 15 natural populations of owned and unowned cats (Felis silvestris catus), Preventive Veterinary Medicine 101:250, 2011.

Cats are susceptible to a number of important viruses that can cause significant disease. The living conditions and behavior of various cat populations will affect their susceptibility and risk of exposure to these viruses. The investigators examined 15 populations of non-sterilized unvaccinated cats living in the same area of France. These populations had one of two different lifestyles – owned (sheltered and fed, socialized) and unowned (no shelter or food provided, unsocialized). Blood samples were tested for exposure of the cats to feline herpesvirus (FHV), calicivirus (FCV), parvovirus (FPV), immunodeficiency virus (FIV), and leukemia virus (FeLV). Not surprisingly, the unowned cats were more likely to have been infected with FHV, FCV, and FIV – these viruses largely require direct contact between cats, including fighting. The owned cats were more likely to have been infected with FPV. For each virus, the likelihood of having been infected varied with the population. For example, FIV infection was more likely in older, male, unowned cats; FHV was more likely to infect kittens at an earlier age in unowned versus owned populations; FPV infection was more likely in owned populations perhaps because of shared environments in human settlements. The main crux of this paper was that the epidemiology of a particular virus within cat populations can be affected by their behavior and lifestyle. Failure to consider these aspects can skew results of epidemiologic analyses. For example, when the status of the owned and unowned cats were combined, a different epidemiologic picture was seen for the various viruses examined – the risk factors were different, and included such factors as body mass. Pooling different types of cats in a single sample without taking behavior and lifestyle into account could give a misleading picture of the epidemiology of their viruses. [MK]

Related articles: Pontier D, Fouchet D, Bahi-Jaber N et al: When domestic cat (Felis silvestris catus) population structures interact with their viruses, C R Biol 332:321, 2009.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

Hellard E, Fouchet D, Santin-Janin H et al: When cats' ways of life interact with their viruses: a study in 15 natural populations of owned and unowned cats (Felis silvestris catus), Preventive Veterinary Medicine 101:250, 2011.

Cats are susceptible to a number of important viruses that can cause significant disease. The living conditions and behavior of various cat populations will affect their susceptibility and risk of exposure to these viruses. The investigators examined 15 populations of non-sterilized unvaccinated cats living in the same area of France. These populations had one of two different lifestyles – owned (sheltered and fed, socialized) and unowned (no shelter or food provided, unsocialized). Blood samples were tested for exposure of the cats to feline herpesvirus (FHV), calicivirus (FCV), parvovirus (FPV), immunodeficiency virus (FIV), and leukemia virus (FeLV). Not surprisingly, the unowned cats were more likely to have been infected with FHV, FCV, and FIV – these viruses largely require direct contact between cats, including fighting. The owned cats were more likely to have been infected with FPV. For each virus, the likelihood of having been infected varied with the population. For example, FIV infection was more likely in older, male, unowned cats; FHV was more likely to infect kittens at an earlier age in unowned versus owned populations; FPV infection was more likely in owned populations perhaps because of shared environments in human settlements. The main crux of this paper was that the epidemiology of a particular virus within cat populations can be affected by their behavior and lifestyle. Failure to consider these aspects can skew results of epidemiologic analyses. For example, when the status of the owned and unowned cats were combined, a different epidemiologic picture was seen for the various viruses examined – the risk factors were different, and included such factors as body mass. Pooling different types of cats in a single sample without taking behavior and lifestyle into account could give a misleading picture of the epidemiology of their viruses. [MK]

Related articles: Pontier D, Fouchet D, Bahi-Jaber N et al: When domestic cat (Felis silvestris catus) population structures interact with their viruses, C R Biol 332:321, 2009.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

Read More

FeLV and Feline Lymphoma

Weiss ATA, Klopfleisch R, Gruber AD: Prevalence of feline leukaemia provirus DNA in feline lymphomas, Journal of Feline Medicine & Surgery 12: 929, 2010.

Feline leukemia virus (FeLV) is an important pathogen of cats. Since development of screening assays and vaccines for FeLV, the prevalence of persistently infected cats has decreased. Recent studies have shown that the FeLV genetic material remains in cats exposed to the virus, though viral replication may not occur. Concern exists that this persistent viral DNA may contribute to development of lymphoma in cats. To determine if an association exists, samples from 50 cases of lymphoma were tested for the presence of FeLV. Viral DNA was detected in a high percentage of all types of feline lymphomas by these investigators. Thus, though the prevalence of FeLV infection as well as lymphoma has decreased with the development of control measures for FeLV, a significant portion of feline lymphomas appear to involve FeLV genetic material. [MK]

Related articles:

Stutzer B, Simon K, Lutz H et al: Incidence of persistent viraemia and latent feline leukaemia virus infection in cats with lymphoma, Journal of Feline Medicine & Surgery 13: 81, 2011.

More on cat health: Winn Feline Foundation Library

Join us on Facebook

Follow us on Twitter

Weiss ATA, Klopfleisch R, Gruber AD: Prevalence of feline leukaemia provirus DNA in feline lymphomas, Journal of Feline Medicine & Surgery 12: 929, 2010.

Feline leukemia virus (FeLV) is an important pathogen of cats. Since development of screening assays and vaccines for FeLV, the prevalence of persistently infected cats has decreased. Recent studies have shown that the FeLV genetic material remains in cats exposed to the virus, though viral replication may not occur. Concern exists that this persistent viral DNA may contribute to development of lymphoma in cats. To determine if an association exists, samples from 50 cases of lymphoma were tested for the presence of FeLV. Viral DNA was detected in a high percentage of all types of feline lymphomas by these investigators. Thus, though the prevalence of FeLV infection as well as lymphoma has decreased with the development of control measures for FeLV, a significant portion of feline lymphomas appear to involve FeLV genetic material. [MK]

Related articles:

Stutzer B, Simon K, Lutz H et al: Incidence of persistent viraemia and latent feline leukaemia virus infection in cats with lymphoma, Journal of Feline Medicine & Surgery 13: 81, 2011.

More on cat health: Winn Feline Foundation Library

Join us on Facebook

Follow us on Twitter

Read More

Feline Leukemia Virus & Bartonella Infections

Buchmann AU, Kershaw O, Kempf VA, et al. Does a feline leukemia virus infection pave the way for Bartonella henselae infection in cats? J Clin Microbiol 2010;48:3295-3300.

Bartonella henselae is the agent of cat scratch fever in humans. Domestic cats are a known reservoir of this bacterium for human infection via scratches and bites. In cats, it has been associated with a number of disorders including gingivitis, stomatitis, and urinary tract diseases among others. In humans with immunosuppressive disorders, disease following Bartonella infection is much more severe; the impact of immunosuppression in cats on Bartonella infections has not been examined. These investigators collected tissue samples from nearly 150 cats euthanized at German animal shelters over a two year period and assessed them for coinfection with Bartonella and feline parvovirus (FPV), feline leukemia virus (FeLV), and/or feline immunodeficiency virus (FIV). The overall rate of Bartonella infection was nearly 8%. Infection of cats with this bacterium was significantly correlated with FeLV infection: of six cats with FeLV, four also had Bartonella henselae; three of these four were latently infected with FeLV (positive for viral genetic material but negative for viral proteins). No correlation with either FIV or FPV was found. The authors concluded that FeLV may enhance the susceptibility to or persistence of B henselae infection. [MK]

Related articles:

Belgard S, Truyen U, Thibault JC, et al. Relevance of feline calicivirus, feline immunodeficiency virus, feline leukemia virus, feline herpesvirus and Bartonella henselae in cats with chronic gingivostomatitis. Berl Munch Tierarztl Wochenschr 2010;123:369-376.

More on cat health: Winn Feline Foundation Library

Join us on Facebook

Follow us on Twitter

Buchmann AU, Kershaw O, Kempf VA, et al. Does a feline leukemia virus infection pave the way for Bartonella henselae infection in cats? J Clin Microbiol 2010;48:3295-3300.

Bartonella henselae is the agent of cat scratch fever in humans. Domestic cats are a known reservoir of this bacterium for human infection via scratches and bites. In cats, it has been associated with a number of disorders including gingivitis, stomatitis, and urinary tract diseases among others. In humans with immunosuppressive disorders, disease following Bartonella infection is much more severe; the impact of immunosuppression in cats on Bartonella infections has not been examined. These investigators collected tissue samples from nearly 150 cats euthanized at German animal shelters over a two year period and assessed them for coinfection with Bartonella and feline parvovirus (FPV), feline leukemia virus (FeLV), and/or feline immunodeficiency virus (FIV). The overall rate of Bartonella infection was nearly 8%. Infection of cats with this bacterium was significantly correlated with FeLV infection: of six cats with FeLV, four also had Bartonella henselae; three of these four were latently infected with FeLV (positive for viral genetic material but negative for viral proteins). No correlation with either FIV or FPV was found. The authors concluded that FeLV may enhance the susceptibility to or persistence of B henselae infection. [MK]

Related articles:

Belgard S, Truyen U, Thibault JC, et al. Relevance of feline calicivirus, feline immunodeficiency virus, feline leukemia virus, feline herpesvirus and Bartonella henselae in cats with chronic gingivostomatitis. Berl Munch Tierarztl Wochenschr 2010;123:369-376.

More on cat health: Winn Feline Foundation Library

Join us on Facebook

Follow us on Twitter

Read More

New In-Clinic Test for FeLV and FIV

Sand C, Englert T, Egberink H et al: Evaluation of a new in-clinic test system to detect feline immunodeficiency virus and feline leukemia virus infection, Vet Clin Pathol 39:210, 2009.

Feline leukemia (FeLV) and feline immunodeficiency virus (FIV) are both important pathogens of cats that often result in lifelong infection. Routine testing as well as testing of clinically ill cats is recommended, and is usually done using in-clinic test kits. For FeLV, these assays detect a viral protein, while for FIV, virus-specific antibody is detected. A new test system, Anigen Rapid FIV Ab/FeLV Ag test kit is now available on the European market. These investigators examined the diagnostic sensitivity and specificity of this new test kit on 300 samples using western blot as the gold standard for FIV infection, and polymerase chain reaction for FeLV infection; in addition, results were compared to those attained using the most commonly-used kit made by IDEXX (SNAP Combo). In comparison to the gold standard for FIV, the new Anigen test had a sensitivity of 88.9% and specificity of 97.7%, and for FeLV, a sensitivity of 40% and a specificity of 100%. In comparing to the IDEXX Combo SNAP test for FIV testing, the Anigen assay had one false positive result; the SNAP test had no false positive results. Both kits had one false negative result. For FeLV testing, neither kit had a false positive result, but the Anigen kit had 9 false negatives, while the SNAP kit had 7 false negative results. The investigators concluded that the new test performed very well, similar in performance to the SNAP Combo test. For both kits, any positive result should be confirmed with a second, more sensitive test, especially in healthy cats. [MK]

Related articles:
Levy J, Crawford C, Hartmann K et al: 2008 American Association of Feline Practitioners' feline retrovirus management guidelines, J Feline Med Surg 10:300, 2008.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

Sand C, Englert T, Egberink H et al: Evaluation of a new in-clinic test system to detect feline immunodeficiency virus and feline leukemia virus infection, Vet Clin Pathol 39:210, 2009.

Feline leukemia (FeLV) and feline immunodeficiency virus (FIV) are both important pathogens of cats that often result in lifelong infection. Routine testing as well as testing of clinically ill cats is recommended, and is usually done using in-clinic test kits. For FeLV, these assays detect a viral protein, while for FIV, virus-specific antibody is detected. A new test system, Anigen Rapid FIV Ab/FeLV Ag test kit is now available on the European market. These investigators examined the diagnostic sensitivity and specificity of this new test kit on 300 samples using western blot as the gold standard for FIV infection, and polymerase chain reaction for FeLV infection; in addition, results were compared to those attained using the most commonly-used kit made by IDEXX (SNAP Combo). In comparison to the gold standard for FIV, the new Anigen test had a sensitivity of 88.9% and specificity of 97.7%, and for FeLV, a sensitivity of 40% and a specificity of 100%. In comparing to the IDEXX Combo SNAP test for FIV testing, the Anigen assay had one false positive result; the SNAP test had no false positive results. Both kits had one false negative result. For FeLV testing, neither kit had a false positive result, but the Anigen kit had 9 false negatives, while the SNAP kit had 7 false negative results. The investigators concluded that the new test performed very well, similar in performance to the SNAP Combo test. For both kits, any positive result should be confirmed with a second, more sensitive test, especially in healthy cats. [MK]

Related articles:
Levy J, Crawford C, Hartmann K et al: 2008 American Association of Feline Practitioners' feline retrovirus management guidelines, J Feline Med Surg 10:300, 2008.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

Read More

FeLV and FIV in Germany

Gleich SE, Krieger S, Hartmann K. Prevalence of feline immunodeficiency virus and feline leukaemia virus among client-owned cats and risk factors for infection in Germany. J Feline Med Surg. 2009;11(12):985-992.

This study determined prevalence and risk factors for retrovirus infection in a large population of cats in Germany over a 10-year period. Client-owned cats (17,462) were tested for the presence of feline immunodeficiency virus (FIV) antibodies or feline leukaemia virus (FeLV) antigen. A subset of 100 cats was evaluated to determine their survival times. Of the 17,289 cats, 563 tested positive for anitibodies against FIV. The prevalence was 3.2% and did not change significantly between 1993 and 2002. FeLV antigen was found in 638 cats. The prevalence of FeLV decreased significantly during this time from 6% to 1%. Forty-two cats were positive for both viruses. Living in a multi-cat household did not influence the risk of retroviral infection. Risk factors for FIV infection were male gender, older age, mixed breed, access to outdoor, aggressive behavior, and FeLV co-infection. Risk factors for FeLV infection included contact with other cats, aggressive behavior, and FIV co-infection. Vaccination and testing programs appear to be effective in decreasing FeLV infection. The median survival time of FIV-infected cats was not significantly different from non-infected cats. FeLV-infected cats had significantly shorter median survival times than non-infected cats. [VT]

Related articles:
Little S, Sears W, Lachtara J, Bienzle D. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in Canada. Can Vet J. 2009;50(6):644-648.

Levy JK, Scott HM, Lachtara JL, Crawford PC. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity. J Am Vet Med Assoc. Feb 1 2006;228(3):371-376.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

New for 2010: Subscribe to our e-newsletter

Gleich SE, Krieger S, Hartmann K. Prevalence of feline immunodeficiency virus and feline leukaemia virus among client-owned cats and risk factors for infection in Germany. J Feline Med Surg. 2009;11(12):985-992.

This study determined prevalence and risk factors for retrovirus infection in a large population of cats in Germany over a 10-year period. Client-owned cats (17,462) were tested for the presence of feline immunodeficiency virus (FIV) antibodies or feline leukaemia virus (FeLV) antigen. A subset of 100 cats was evaluated to determine their survival times. Of the 17,289 cats, 563 tested positive for anitibodies against FIV. The prevalence was 3.2% and did not change significantly between 1993 and 2002. FeLV antigen was found in 638 cats. The prevalence of FeLV decreased significantly during this time from 6% to 1%. Forty-two cats were positive for both viruses. Living in a multi-cat household did not influence the risk of retroviral infection. Risk factors for FIV infection were male gender, older age, mixed breed, access to outdoor, aggressive behavior, and FeLV co-infection. Risk factors for FeLV infection included contact with other cats, aggressive behavior, and FIV co-infection. Vaccination and testing programs appear to be effective in decreasing FeLV infection. The median survival time of FIV-infected cats was not significantly different from non-infected cats. FeLV-infected cats had significantly shorter median survival times than non-infected cats. [VT]

Related articles:
Little S, Sears W, Lachtara J, Bienzle D. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in Canada. Can Vet J. 2009;50(6):644-648.

Levy JK, Scott HM, Lachtara JL, Crawford PC. Seroprevalence of feline leukemia virus and feline immunodeficiency virus infection among cats in North America and risk factors for seropositivity. J Am Vet Med Assoc. Feb 1 2006;228(3):371-376.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

New for 2010: Subscribe to our e-newsletter

Read More

Feline Leukemia Virus

Stutzer B, Muller F, Majzoub M, et al. Role of latent feline leukemia virus infection in nonregenerative cytopenias of cats. J Vet Intern Med. Nov 17 2009.

Nonregenerative cytopenias such as nonregenerative anemia, neutropenia, and thrombocytopenia are a common finding in cats infected with feline leukemia virus (FeLV). The objective of this study was to assess the role of latent FeLV infection in bone marrow in cats with nonregenerative cytopenias that had a negative FeLV antigen blood test. Thirty-seven cats were included in the patient group meeting inclusion criteria of a nonregenerative cytopenia of unknown origin and a negative FeLV antigen test result. The group’s results were compared to two control groups that also totaled 37 cats. Whole blood and bone marrow samples were tested for FeLV using two different PCR assays. Results indicated that PCR from bone marrow could be considered a more sensitive method to detect FeLV latency than PCR of whole blood. Two of the 37 cats (5.4%) in the patient groups were positive on bone marrow PCR results and were considered infected with FeLV. The latent FeLV infection in those two cats was the possible cause of the observed nonregenerative cytopenia. [VT]

Related articles:
Herring ES, Troy GC, Toth TE, Forrester SD, Weigt LA, Herring IP. Detection of feline leukaemia virus in blood and bone marrow of cats with varying suspicion of latent infection. J Feline Med Surg. Sep 2001;3(3):133-141.

Torres AN, Mathiason CK, Hoover EA. Re-examination of feline leukemia virus: host relationships using real-time PCR. Virology. Feb 5 2005;332(1):272-283.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

Stutzer B, Muller F, Majzoub M, et al. Role of latent feline leukemia virus infection in nonregenerative cytopenias of cats. J Vet Intern Med. Nov 17 2009.

Nonregenerative cytopenias such as nonregenerative anemia, neutropenia, and thrombocytopenia are a common finding in cats infected with feline leukemia virus (FeLV). The objective of this study was to assess the role of latent FeLV infection in bone marrow in cats with nonregenerative cytopenias that had a negative FeLV antigen blood test. Thirty-seven cats were included in the patient group meeting inclusion criteria of a nonregenerative cytopenia of unknown origin and a negative FeLV antigen test result. The group’s results were compared to two control groups that also totaled 37 cats. Whole blood and bone marrow samples were tested for FeLV using two different PCR assays. Results indicated that PCR from bone marrow could be considered a more sensitive method to detect FeLV latency than PCR of whole blood. Two of the 37 cats (5.4%) in the patient groups were positive on bone marrow PCR results and were considered infected with FeLV. The latent FeLV infection in those two cats was the possible cause of the observed nonregenerative cytopenia. [VT]

Related articles:
Herring ES, Troy GC, Toth TE, Forrester SD, Weigt LA, Herring IP. Detection of feline leukaemia virus in blood and bone marrow of cats with varying suspicion of latent infection. J Feline Med Surg. Sep 2001;3(3):133-141.

Torres AN, Mathiason CK, Hoover EA. Re-examination of feline leukemia virus: host relationships using real-time PCR. Virology. Feb 5 2005;332(1):272-283.

More on cat health: Winn Feline Foundation Library
Join us on Facebook
Follow us on Twitter

Read More