Thyroid Hormone Testing

Rutland BE, Nachreiner RF, Kruger JM. Optimal testing for thyroid hormone concentration after treatment with methimazole in healthy and hyperthyroid cats. J Vet Intern Med 2009;23:1025-1030.

Hyperthyroidism is one of the most common endocrinopathies of cats and its prevalence is increasing in recent years. Methimazole is commonly used to treat hyperthyroidism and its action is to suppress thyroid hormone synthesis. The optimal time for blood sampling to monitor therapeutic efficacy, and the amount of variation in thyroid hormone concentrations 24 hours post administration of methimazole have not been determined. In this study, healthy cats were given steadily increasing doses of oral methimazole until a steady state of thyroid suppression was achieved. It was found that there is a significant and sustained suppression of total thyroxine (TT4), total tri-iodothyronine (TT3), free T3, and free T4 concentrations for 24 hours after a once daily methimazole administration in healthy cats. The time to thyroid gland suppression in healthy cats was 2-5 weeks. In addition, a retrospective study of 889 thyroid profiles from methimazole-treated hyperthyroid cats was reviewed. The review noted that in hyperthyroid cats, there was no significant relationship between thyroid hormone concentrations and time post-pill or dosing interval. The conclusion was timing of blood sampling after oral methimazole administration does not appear to be a significant factor when assessing response to treatment. [VT]
>> PubMed Abstract

Related articles:
Trepanier L, Hoffman S, Kroll M, et al. Efficacy and safety of once versus twice daily administration of methimazole in cats with hyperthyroidism. J Am Vet Med Assoc 2003;222:954-958.
>> PubMed Abstract

Trepanier LA. Pharmacologic management of feline hyperthyroidism. Vet Clin North Am Small Anim Pract 2007;37:775-788, vii.
>> PubMed Abstract

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Rutland BE, Nachreiner RF, Kruger JM. Optimal testing for thyroid hormone concentration after treatment with methimazole in healthy and hyperthyroid cats. J Vet Intern Med 2009;23:1025-1030.

Hyperthyroidism is one of the most common endocrinopathies of cats and its prevalence is increasing in recent years. Methimazole is commonly used to treat hyperthyroidism and its action is to suppress thyroid hormone synthesis. The optimal time for blood sampling to monitor therapeutic efficacy, and the amount of variation in thyroid hormone concentrations 24 hours post administration of methimazole have not been determined. In this study, healthy cats were given steadily increasing doses of oral methimazole until a steady state of thyroid suppression was achieved. It was found that there is a significant and sustained suppression of total thyroxine (TT4), total tri-iodothyronine (TT3), free T3, and free T4 concentrations for 24 hours after a once daily methimazole administration in healthy cats. The time to thyroid gland suppression in healthy cats was 2-5 weeks. In addition, a retrospective study of 889 thyroid profiles from methimazole-treated hyperthyroid cats was reviewed. The review noted that in hyperthyroid cats, there was no significant relationship between thyroid hormone concentrations and time post-pill or dosing interval. The conclusion was timing of blood sampling after oral methimazole administration does not appear to be a significant factor when assessing response to treatment. [VT]
>> PubMed Abstract

Related articles:
Trepanier L, Hoffman S, Kroll M, et al. Efficacy and safety of once versus twice daily administration of methimazole in cats with hyperthyroidism. J Am Vet Med Assoc 2003;222:954-958.
>> PubMed Abstract

Trepanier LA. Pharmacologic management of feline hyperthyroidism. Vet Clin North Am Small Anim Pract 2007;37:775-788, vii.
>> PubMed Abstract

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Feline Injection Site Sarcomas

Shaw, S. C., M. S. Kent, et al. (2009). "Temporal changes in characteristics of injection-site sarcomas in cats: 392 cases (1990-2006)." Journal of the American Veterinary Medical Association 234(3): 376-380.

The first suggestion that vaccine injections and the development of sarcomas in cats were associated was in October, 1991. Histologic and epidemiologic evaluations have supported a causal relationship between injections and the development of sarcomas. The most commonly indicated vaccines were those for rabies virus and feline leukemia (FeLV). In November 1996, the Vaccine-Associated Feline Sarcoma Task Force (VAFSTF) was formed and one of its original tasks was to standardize injection sites. Prior to the recommendations, the majority of vaccinations were given in the interscapular region. The VAFSTF recommendations were to administer the rabies vaccine in the right rear leg as distal as possible, the FeLV vaccine in the left rear leg as distal as possible, and the FVRCP in the right shoulder. This study examined injection-site sarcomas (ISS) in 392 cats in order to evaluate changes in anatomic location and histologic classification of these sarcomas and the signalment of affected cats before and after publication of the VAFSTF recommendations. The results of the study indicated a high proportion of ISS in the interscapular region prior to publication of the recommendations (53.4%) and a significant proportional decrease (39.5%) after publication and likely adoption of the recommendations. There was also a significant decrease in lateral thoracic ISS that suggested tumors in these locations might have been caused by interscapular injections that were aberrantly administered. However, after 1996 the proportion of ISS on the limbs of cats and on the lateral aspects of the abdomen increased. This creates cause for concern because lateral abdominal tumors can be challenging, if not more difficult to treat, than those in the interscapular region. These results lead the authors to recommend that the VAFSTF recommendations be adhered to more strictly with emphasis on placement of injections in limbs as distally as possible. [VT]
>> PubMed Abstract

Related articles:
Romanelli, G., L. Marconato, et al. (2008). "Analysis of prognostic factors associated with injection-site sarcomas in cats: 57 cases (2001-2007)." J Am Vet Med Assoc 232(8): 1193-9.
>> PubMed Abstract

Kirpensteijn, J. (2006). "Feline injection site-associated sarcoma: Is it a reason to critically evaluate our vaccination policies?" Vet Microbiol 117(1): 59-65.
>> PubMed Abstract

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Shaw, S. C., M. S. Kent, et al. (2009). "Temporal changes in characteristics of injection-site sarcomas in cats: 392 cases (1990-2006)." Journal of the American Veterinary Medical Association 234(3): 376-380.

The first suggestion that vaccine injections and the development of sarcomas in cats were associated was in October, 1991. Histologic and epidemiologic evaluations have supported a causal relationship between injections and the development of sarcomas. The most commonly indicated vaccines were those for rabies virus and feline leukemia (FeLV). In November 1996, the Vaccine-Associated Feline Sarcoma Task Force (VAFSTF) was formed and one of its original tasks was to standardize injection sites. Prior to the recommendations, the majority of vaccinations were given in the interscapular region. The VAFSTF recommendations were to administer the rabies vaccine in the right rear leg as distal as possible, the FeLV vaccine in the left rear leg as distal as possible, and the FVRCP in the right shoulder. This study examined injection-site sarcomas (ISS) in 392 cats in order to evaluate changes in anatomic location and histologic classification of these sarcomas and the signalment of affected cats before and after publication of the VAFSTF recommendations. The results of the study indicated a high proportion of ISS in the interscapular region prior to publication of the recommendations (53.4%) and a significant proportional decrease (39.5%) after publication and likely adoption of the recommendations. There was also a significant decrease in lateral thoracic ISS that suggested tumors in these locations might have been caused by interscapular injections that were aberrantly administered. However, after 1996 the proportion of ISS on the limbs of cats and on the lateral aspects of the abdomen increased. This creates cause for concern because lateral abdominal tumors can be challenging, if not more difficult to treat, than those in the interscapular region. These results lead the authors to recommend that the VAFSTF recommendations be adhered to more strictly with emphasis on placement of injections in limbs as distally as possible. [VT]
>> PubMed Abstract

Related articles:
Romanelli, G., L. Marconato, et al. (2008). "Analysis of prognostic factors associated with injection-site sarcomas in cats: 57 cases (2001-2007)." J Am Vet Med Assoc 232(8): 1193-9.
>> PubMed Abstract

Kirpensteijn, J. (2006). "Feline injection site-associated sarcoma: Is it a reason to critically evaluate our vaccination policies?" Vet Microbiol 117(1): 59-65.
>> PubMed Abstract

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Understanding Feline Immunodeficiency Virus Infection

Grant, C. K., E. A. Fink, et al. (2009). "Improved health and survival of FIV-infected cats is associated with the presence of autoantibodies to the primary receptor, CD134." Proc Natl Acad Sci U S A 106(47): 19980-5.

Feline immunodeficiency virus (FIV) is an important pathogen of cats, causing lifelong infection and ultimately death from immunosuppression. These researchers examined antibody levels to various viral and cellular proteins in stored serum samples collected from FIV-infected cats over 30 years. They found very strong antiviral responses to several virus proteins, including the major surface protein of the virus. Interestingly, they also found evidence of antibodies to the feline cellular protein used by the virus to attach to and infect the cell (CD134). Even more remarkable, they found that this antibody only bound the cellular protein when the viral attachment protein was bound to it. Thus, binding of the virus to this cellular protein reveals a site on the cellular protein that is not normally “visible” to the immune system of the cat, leading to antibody production to this cellular protein. In a laboratory experiment, they found that not only did antibodies to the virus protein inhibited virus infection, but antibodies to the cellular protein targeted by the virus did so as well. When they evaluated antibody levels from cats of known health status, the highest percentage of cats positive for this cell-specific antibody were healthy and asymptomatic. In contrast, samples negative for this antibody were largely acquired from cats that were ill. In assessing viral load in the blood of 20 infected cats and comparing that to antibody levels to the CD134, the researchers found that cats with high viral loads (poorer prognosis) did not have measurable levels of antibody to the CD134. The findings are consistent with a role for anti-cell receptor antibodies in protection from virus spread and disease progression. [MK]
>> Free full text article

Related articles:
Hosie, M. J., D. Addie, et al. (2009). "Feline immunodeficiency ABCD guidelines on prevention and management." J Feline Med Surg 11(7): 575-84.
>> Free full text article

Levy, J., C. Crawford, et al. (2008). "2008 American Association of Feline Practitioners' feline retrovirus management guidelines." Journal of Feline Medicine & Surgery 10(3): 300-316.
>> Free full text article

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Grant, C. K., E. A. Fink, et al. (2009). "Improved health and survival of FIV-infected cats is associated with the presence of autoantibodies to the primary receptor, CD134." Proc Natl Acad Sci U S A 106(47): 19980-5.

Feline immunodeficiency virus (FIV) is an important pathogen of cats, causing lifelong infection and ultimately death from immunosuppression. These researchers examined antibody levels to various viral and cellular proteins in stored serum samples collected from FIV-infected cats over 30 years. They found very strong antiviral responses to several virus proteins, including the major surface protein of the virus. Interestingly, they also found evidence of antibodies to the feline cellular protein used by the virus to attach to and infect the cell (CD134). Even more remarkable, they found that this antibody only bound the cellular protein when the viral attachment protein was bound to it. Thus, binding of the virus to this cellular protein reveals a site on the cellular protein that is not normally “visible” to the immune system of the cat, leading to antibody production to this cellular protein. In a laboratory experiment, they found that not only did antibodies to the virus protein inhibited virus infection, but antibodies to the cellular protein targeted by the virus did so as well. When they evaluated antibody levels from cats of known health status, the highest percentage of cats positive for this cell-specific antibody were healthy and asymptomatic. In contrast, samples negative for this antibody were largely acquired from cats that were ill. In assessing viral load in the blood of 20 infected cats and comparing that to antibody levels to the CD134, the researchers found that cats with high viral loads (poorer prognosis) did not have measurable levels of antibody to the CD134. The findings are consistent with a role for anti-cell receptor antibodies in protection from virus spread and disease progression. [MK]
>> Free full text article

Related articles:
Hosie, M. J., D. Addie, et al. (2009). "Feline immunodeficiency ABCD guidelines on prevention and management." J Feline Med Surg 11(7): 575-84.
>> Free full text article

Levy, J., C. Crawford, et al. (2008). "2008 American Association of Feline Practitioners' feline retrovirus management guidelines." Journal of Feline Medicine & Surgery 10(3): 300-316.
>> Free full text article

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Successful Cat Adoptions from Shelters

Weiss, E. and S. Gramann (2009). "A comparison of attachment levels of adopters of cats: fee-based adoptions versus free adoptions" J Appl Anim Welf Sci 12(4): 360-370.

Some involved with animal welfare are critical of free adoptions of adult cats, believing it devalues the cat in the adopter’s eyes, or it may attract adopters who are unable to fulfill the financial responsibilities of cat ownership. Advocates believe waiving the fee for adult cats will enhance rates of adoptions, and provide opportunities to educate owners who may otherwise adopt from neighbors or may respond to “free to good home” ads. This study examined the attachment of adopters to their cats in relation to payment or fee waiver for adoption. One hundred seventy-three adopters from a rescue facility in Maine participated in the study, of which 95 paid no adoption fee for their adult cat, and 78 paid a $75 adoption fee. Whether or not an adopter paid the fee was a function of when the shelter was running promotional campaigns for adoptions by offering fee waivers. Using an attachment scale consisting of a series of statements that the adopters would indicate agreement or disagreement (1-strongly disagree, 4-strongly agree), pet attachment was rated. Statistical analysis of the results showed no significant difference in the two groups’ attachment to their adopted cat. The authors conclude “implementing a free adult cat adoption program in shelters around the country could dramatically affect the lives of thousands of shelter cats who otherwise either would reside in the shelter for months awaiting adoption or be euthanized. The ultimate goal of shelters is to adopt their animals into loving homes with families who are committed to the success of their pet. The free adult cat adoption program may accomplish these goals, and shelters can feel confident in implementing the program.” [MK]
>> Journal Abstract

Related articles:
Shore, E. R. (2005). "Returning a recently adopted companion animal: adopters' reasons for and reactions to the failed adoption experience." J Appl Anim Welf Sci 8(3): 187-198.
>> PubMed Abstract

Neidhart, L. and R. Boyd (2002). "Companion animal adoption study." J Appl Anim Welf Sci 5(3): 175-192.
>> PubMed Abstract

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Weiss, E. and S. Gramann (2009). "A comparison of attachment levels of adopters of cats: fee-based adoptions versus free adoptions" J Appl Anim Welf Sci 12(4): 360-370.

Some involved with animal welfare are critical of free adoptions of adult cats, believing it devalues the cat in the adopter’s eyes, or it may attract adopters who are unable to fulfill the financial responsibilities of cat ownership. Advocates believe waiving the fee for adult cats will enhance rates of adoptions, and provide opportunities to educate owners who may otherwise adopt from neighbors or may respond to “free to good home” ads. This study examined the attachment of adopters to their cats in relation to payment or fee waiver for adoption. One hundred seventy-three adopters from a rescue facility in Maine participated in the study, of which 95 paid no adoption fee for their adult cat, and 78 paid a $75 adoption fee. Whether or not an adopter paid the fee was a function of when the shelter was running promotional campaigns for adoptions by offering fee waivers. Using an attachment scale consisting of a series of statements that the adopters would indicate agreement or disagreement (1-strongly disagree, 4-strongly agree), pet attachment was rated. Statistical analysis of the results showed no significant difference in the two groups’ attachment to their adopted cat. The authors conclude “implementing a free adult cat adoption program in shelters around the country could dramatically affect the lives of thousands of shelter cats who otherwise either would reside in the shelter for months awaiting adoption or be euthanized. The ultimate goal of shelters is to adopt their animals into loving homes with families who are committed to the success of their pet. The free adult cat adoption program may accomplish these goals, and shelters can feel confident in implementing the program.” [MK]
>> Journal Abstract

Related articles:
Shore, E. R. (2005). "Returning a recently adopted companion animal: adopters' reasons for and reactions to the failed adoption experience." J Appl Anim Welf Sci 8(3): 187-198.
>> PubMed Abstract

Neidhart, L. and R. Boyd (2002). "Companion animal adoption study." J Appl Anim Welf Sci 5(3): 175-192.
>> PubMed Abstract

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Evaluating Feline Coagulation

Tholen, I., C. Weingart, et al. (2009). "Concentration of D-dimers in healthy cats and sick cats with and without disseminated intravascular coagulation (DIC)." J Feline Med Surg 11(10): 842-6.

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by excessive activation and loss of regulation of coagulation. This leads to a potentially life-threatening deposition of fibrin throughout the microvasculature. This syndrome usually derives from one of various underlying diseases. D-dimers concentrations are considered an important criterion for diagnosis of DIC in humans. This study measured D-dimers concentrations in 48 cats with various underlying diseases and 20 healthy cats. Twelve of the 48 sick cats were diagnosed with DIC based on the presence of at least three of the following criteria: thrombocytopenia, prolonged activated partial thromboplastin time, prothrombin time or thrombin time, schistocytes, and/or a reduced antithrombin activity. The D-dimer latex agglutination test (LA) was positive for eight of 12 cats with DIC and for 16 of 36 sick cats without DIC. All healthy control cats had negative D-dimer LA tests. The comparison of sick cats with DIC and those without DIC revealed a specificity and sensitivity of the test of 56% and 67%; comparison between healthy cats and sick cats with DIC revealed a specificity and sensitivity of 100% and 67%. The D-dimer LA test appears to have limited value for diagnosis of DIC in cats. [VT]
>> PubMed Abstract

Related articles:
Brazzell, J. L. and D. L. Borjesson (2007). "Evaluation of plasma antithrombin activity and D-dimer concentration in populations of healthy cats, clinically ill cats, and cats with cardiomyopathy." Vet Clin Pathol 36(1): 79-84.
>> PubMed Abstract

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Tholen, I., C. Weingart, et al. (2009). "Concentration of D-dimers in healthy cats and sick cats with and without disseminated intravascular coagulation (DIC)." J Feline Med Surg 11(10): 842-6.

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by excessive activation and loss of regulation of coagulation. This leads to a potentially life-threatening deposition of fibrin throughout the microvasculature. This syndrome usually derives from one of various underlying diseases. D-dimers concentrations are considered an important criterion for diagnosis of DIC in humans. This study measured D-dimers concentrations in 48 cats with various underlying diseases and 20 healthy cats. Twelve of the 48 sick cats were diagnosed with DIC based on the presence of at least three of the following criteria: thrombocytopenia, prolonged activated partial thromboplastin time, prothrombin time or thrombin time, schistocytes, and/or a reduced antithrombin activity. The D-dimer latex agglutination test (LA) was positive for eight of 12 cats with DIC and for 16 of 36 sick cats without DIC. All healthy control cats had negative D-dimer LA tests. The comparison of sick cats with DIC and those without DIC revealed a specificity and sensitivity of the test of 56% and 67%; comparison between healthy cats and sick cats with DIC revealed a specificity and sensitivity of 100% and 67%. The D-dimer LA test appears to have limited value for diagnosis of DIC in cats. [VT]
>> PubMed Abstract

Related articles:
Brazzell, J. L. and D. L. Borjesson (2007). "Evaluation of plasma antithrombin activity and D-dimer concentration in populations of healthy cats, clinically ill cats, and cats with cardiomyopathy." Vet Clin Pathol 36(1): 79-84.
>> PubMed Abstract

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Aglepristone for Feline Mammary Hyperplasia

Jurka, P. and A. Max (2009). "Treatment of fibroadenomatosis in 14 cats with aglespristone - changes in blood parameters and follow-up." Vet Record 165(22): 657-660.

Mammary hyperplasia (also called fibroadenomatosis or fibroadenomatous hyperplasia) is a benign inflammatory condition commonly seen in young cycling queens. It may also be seen in pregnant queens, and in male or female cats treated with progestins. The hyperplasia can be severe, leading to tissue necrosis, ulceration and infection. The etiology is suspected to be an exaggerated response to natural progesterone or synthetic progestins, but the disease is also rarely reported in sterilized male or female cats with no history of progestin therapy. In spayed queens, ovarian remnant syndrome may be the initiating cause. Many drug therapies have been tried, but the current drug of choice is the progesterone receptor blocker aglepristone (Alizine®, Virbac). Widely available in many countries around the world, it is not available in North America. The drug is also used for pregnancy termination and treatment of cystic endometrial hyperplasia/pyometra complex. The researchers, based in Warsaw, diagnosed 14 female cats with mammary hyperplasia and treated them with aglepristone. The cats were followed up for 12 months after the end of treatment. On average, complete clinical remission of the mammary hyperplasia was achieved 3.9 weeks after initiation of treatment. If the cat had been previously treated with a progestin, a longer treatment period with aglepristone was recommended. After treatment, six queens were bred and four successfully produced at least one litter of kittens. This research confirms the safety and efficacy of aglepristone for treatment of mammary hyperplasia in cats. [SL]
>> Journal Abstract

Related articles:
Gorlinger, S., H. S. Kooistra, et al. (2002). "Treatment of fibroadenomatous hyperplasia in cats with aglepristone." J Vet Intern Med 16(6): 710-3.
>> PubMed Abstract

Nak, D., Y. Nak, et al. (2009). "Follow-up examinations after medical treatment of pyometra in cats with the progesterone-antagonist aglepristone." Journal of Feline Medicine & Surgery 11(6): 499-502.
>> Pubmed Abstract

More on cat health: Winn Feline Foundation Library
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Jurka, P. and A. Max (2009). "Treatment of fibroadenomatosis in 14 cats with aglespristone - changes in blood parameters and follow-up." Vet Record 165(22): 657-660.

Mammary hyperplasia (also called fibroadenomatosis or fibroadenomatous hyperplasia) is a benign inflammatory condition commonly seen in young cycling queens. It may also be seen in pregnant queens, and in male or female cats treated with progestins. The hyperplasia can be severe, leading to tissue necrosis, ulceration and infection. The etiology is suspected to be an exaggerated response to natural progesterone or synthetic progestins, but the disease is also rarely reported in sterilized male or female cats with no history of progestin therapy. In spayed queens, ovarian remnant syndrome may be the initiating cause. Many drug therapies have been tried, but the current drug of choice is the progesterone receptor blocker aglepristone (Alizine®, Virbac). Widely available in many countries around the world, it is not available in North America. The drug is also used for pregnancy termination and treatment of cystic endometrial hyperplasia/pyometra complex. The researchers, based in Warsaw, diagnosed 14 female cats with mammary hyperplasia and treated them with aglepristone. The cats were followed up for 12 months after the end of treatment. On average, complete clinical remission of the mammary hyperplasia was achieved 3.9 weeks after initiation of treatment. If the cat had been previously treated with a progestin, a longer treatment period with aglepristone was recommended. After treatment, six queens were bred and four successfully produced at least one litter of kittens. This research confirms the safety and efficacy of aglepristone for treatment of mammary hyperplasia in cats. [SL]
>> Journal Abstract

Related articles:
Gorlinger, S., H. S. Kooistra, et al. (2002). "Treatment of fibroadenomatous hyperplasia in cats with aglepristone." J Vet Intern Med 16(6): 710-3.
>> PubMed Abstract

Nak, D., Y. Nak, et al. (2009). "Follow-up examinations after medical treatment of pyometra in cats with the progesterone-antagonist aglepristone." Journal of Feline Medicine & Surgery 11(6): 499-502.
>> Pubmed Abstract

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Lysine for Feline Upper Respiratory Tract Disease

Drazenovich, T. L., A. J. Fascetti, et al. (2009). "Effects of dietary lysine supplementation on upper respiratory and ocular disease and detection of infectious organisms in cats within an animal shelter." Am J Vet Res 70(11): 1391-400.

Feline herpesvirus (FHV) is a common cause of respiratory infections in cats housed in shelter situations. Cats latently infected with feline herpesvirus are important sources of the virus for cats that are susceptible to infection. Medications that interfere with latency establishment or reactivation of latent infections would be extremely useful, especially in rescue facilities, where animals are often highly stressed, and have variable vaccination history and immune status. Lysine has shown promise in mediating antiviral effects in cats. These researchers investigated the usefulness of dietary supplementation with lysine for cats in shelters to decrease incidence of infection and detection of FHV shedding. Using 261 adult cats, basal diets (control group) and diets supplemented with lysine (treated group) were fed for four weeks. Unexpectedly, they found that treated cats were actually more likely to manifest severe disease than untreated controls at certain time points in the study (week 4). In addition, FHV was detected more commonly in treated cats (found in week 2 only). A confounding factor was that cats in both groups were also allowed access to commercial diets when hospitalized for illness in addition to the control and test diets. The researchers concluded that continuous dietary supplementation with lysine did not successfully control respiratory disease in a shelter situation, and is not an optimal use of funds in rescue facilities. Bolus treatment of cats with lysine may provide better plasma lysine levels than continuous dietary supplementation, and may provide more beneficial effects.
>> PubMed Abstract

Related articles:
Maggs, D. J., J. E. Sykes, et al. (2007). "Effects of dietary lysine supplementation in cats with enzootic upper respiratory disease." J Feline Med Surg 9(2): 97-108.
>> PubMed Abstract

Rees, T. M. and J. L. Lubinski (2008). "Oral supplementation with L-lysine did not prevent upper respiratory infection in a shelter population of cats." J Feline Med Surg 10(5): 510-3.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
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Drazenovich, T. L., A. J. Fascetti, et al. (2009). "Effects of dietary lysine supplementation on upper respiratory and ocular disease and detection of infectious organisms in cats within an animal shelter." Am J Vet Res 70(11): 1391-400.

Feline herpesvirus (FHV) is a common cause of respiratory infections in cats housed in shelter situations. Cats latently infected with feline herpesvirus are important sources of the virus for cats that are susceptible to infection. Medications that interfere with latency establishment or reactivation of latent infections would be extremely useful, especially in rescue facilities, where animals are often highly stressed, and have variable vaccination history and immune status. Lysine has shown promise in mediating antiviral effects in cats. These researchers investigated the usefulness of dietary supplementation with lysine for cats in shelters to decrease incidence of infection and detection of FHV shedding. Using 261 adult cats, basal diets (control group) and diets supplemented with lysine (treated group) were fed for four weeks. Unexpectedly, they found that treated cats were actually more likely to manifest severe disease than untreated controls at certain time points in the study (week 4). In addition, FHV was detected more commonly in treated cats (found in week 2 only). A confounding factor was that cats in both groups were also allowed access to commercial diets when hospitalized for illness in addition to the control and test diets. The researchers concluded that continuous dietary supplementation with lysine did not successfully control respiratory disease in a shelter situation, and is not an optimal use of funds in rescue facilities. Bolus treatment of cats with lysine may provide better plasma lysine levels than continuous dietary supplementation, and may provide more beneficial effects.
>> PubMed Abstract

Related articles:
Maggs, D. J., J. E. Sykes, et al. (2007). "Effects of dietary lysine supplementation in cats with enzootic upper respiratory disease." J Feline Med Surg 9(2): 97-108.
>> PubMed Abstract

Rees, T. M. and J. L. Lubinski (2008). "Oral supplementation with L-lysine did not prevent upper respiratory infection in a shelter population of cats." J Feline Med Surg 10(5): 510-3.
>> PubMed Abstract

More on cat health: Winn Feline Foundation Library
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