PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

ABSTRACT.- Moura A.B., Costa A.J., Jordão Filho S., Paim B.B., Pinto F.R. & Di Mauro D.C. 2007. Toxoplasma gondii in semen of experimentally infected swine. Pesquisa Veterinária Brasileira 27(10):430-434. Centro de Pesquisas em Sanidade Animal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, SP 14884-900, Brazil. E-mail: a2abm@cav.udesc.br Eight reproductive boars were divided into three groups and inoculated with Toxoplasma gondii [GI (n=3) 1.5x104 oocysts strain P; GII (n=3) 1.0x106 tachyzoites strain RH; and GIII (n=2) non-inoculated control]. Clinical, hematological, parasitemia and serological tests and studies of the parasite in the semen through bioassay and PCR, and in reproductive organs (Bioassay and immunohistochemical analyses) were conducted to evaluate the toxoplasmic infection. Blood and semen were collected on day -2, -1, 1, 3, 5, 7, 9, 11, 14 and weekly up to 84 days post-inoculation (DPI). No clinical or hematimetric alteration was observed in the boars. Parasitemia was detected in one boar inoculated with oocysts at the 7th DPI and in another boar infected with tachyzoites (GII) at the 3rd and 49th DPI. Serological tests revealed antibodies against T. gondii in animals inoculated with oocysts or tachyzoites at the 7th DPI with dilutions of 1:256 and 1:64, which reached peaks of 1:4096 at day 11 and 9, respectively. The bioassays revealed the presence of the parasite in semen samples of a boar inoculated with oocysts (GI) at 3, 49 and 56 DPI and from two boars infected with tachyzoites (GII), one animal at 5 and two animals at 49 days DPI. Mice inoculated with semen from the control group (GIII) remained serologically negative. PCR analysis showed T. gondii DNA in the semen of Boar 1 and Boar 3 inoculated with tachyzoites and oocysts, respectively. The immuno-histochemical tests showed T. gondii in the reproductive organs of Boar 1 and Boar 2, inoculated with tachyzoites and oocysts, respectively. These findings suggest the possible occurrence of venereal transmission of T. gondii in swine.

• Toxoplasmosis swine semen PCR bioassays

Abstract in Portuguese:

ABSTRACT.- Moura A.B., Costa A.J., Jordão Filho S., Paim B.B., Pinto F.R. & Di Mauro D.C. 2007. Toxoplasma gondii in semen of experimentally infected swine. Pesquisa Veterinária Brasileira 27(10):430-434. Centro de Pesquisas em Sanidade Animal, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, SP 14884-900, Brazil. E-mail: a2abm@cav.udesc.br Eight reproductive boars were divided into three groups and inoculated with Toxoplasma gondii [GI (n=3) 1.5x104 oocysts strain P; GII (n=3) 1.0x106 tachyzoites strain RH; and GIII (n=2) non-inoculated control]. Clinical, hematological, parasitemia and serological tests and studies of the parasite in the semen through bioassay and PCR, and in reproductive organs (Bioassay and immunohistochemical analyses) were conducted to evaluate the toxoplasmic infection. Blood and semen were collected on day -2, -1, 1, 3, 5, 7, 9, 11, 14 and weekly up to 84 days post-inoculation (DPI). No clinical or hematimetric alteration was observed in the boars. Parasitemia was detected in one boar inoculated with oocysts at the 7th DPI and in another boar infected with tachyzoites (GII) at the 3rd and 49th DPI. Serological tests revealed antibodies against T. gondii in animals inoculated with oocysts or tachyzoites at the 7th DPI with dilutions of 1:256 and 1:64, which reached peaks of 1:4096 at day 11 and 9, respectively. The bioassays revealed the presence of the parasite in semen samples of a boar inoculated with oocysts (GI) at 3, 49 and 56 DPI and from two boars infected with tachyzoites (GII), one animal at 5 and two animals at 49 days DPI. Mice inoculated with semen from the control group (GIII) remained serologically negative. PCR analysis showed T. gondii DNA in the semen of Boar 1 and Boar 3 inoculated with tachyzoites and oocysts, respectively. The immuno-histochemical tests showed T. gondii in the reproductive organs of Boar 1 and Boar 2, inoculated with tachyzoites and oocysts, respectively. These findings suggest the possible occurrence of venereal transmission of T. gondii in swine.

Abstract in English:

ABSTRACT.- Sanz M.G., Venturini L., Assis R.A., Uzal F., Risso M.A., Idiart J.R. & Perfumo C.J. 2007. Fibrinonecrotic enteritis of piglets in a commercial farm: a postmortem study of the prevalence and the role of lesion associated agents Isospora suis and Clostridium perfringens. Pesquisa Veterinária Brasileira 27(7):297-300. Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, CC 296, B1900 AVW, 60 y 119, La Plata, Argentina. E-mail: cjperfumo@fcv.unlp.edu.ar The objectives were to determine the prevalence of fibrinonecrotic enteritis (FNE) on a farrow-to-finish farm of 1,000 sows, to categorize the pathological changes, and to to investigate the lesion associated agents Isospora suis and Clostridium perfringens. Causes of preweaning mortality (PWM) were classified into 8 categories including FNE. Obtained data were evaluated for statistical significance by adjusted Chi-square analysis. Samples of FNE were taken for complementary studies including a PCR technique for genotyping toxin genes of Clostridium perfringens from gut samples fixed in 10% neutral formalin. From 3,153 piglets examined, less than 1% was classified as FNE. FNE prevalence increased progressively from the first to the third week, the last differing statistically from the others. Eighty percent of gut samples with FNE lesions were positive to Isospora suis, when examined by PCR from 9 severe FNE lesions detected 7 positive samples only for a toxin gene, characteristic of C. perfringens type-A.

• Fibrinonecrotic enteritis piglets prevalence Isospora suis Clostridium perfringens PCR

Abstract in Portuguese:

ABSTRACT.- Sanz M.G., Venturini L., Assis R.A., Uzal F., Risso M.A., Idiart J.R. & Perfumo C.J. 2007. Fibrinonecrotic enteritis of piglets in a commercial farm: a postmortem study of the prevalence and the role of lesion associated agents Isospora suis and Clostridium perfringens. Pesquisa Veterinária Brasileira 27(7):297-300. Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, CC 296, B1900 AVW, 60 y 119, La Plata, Argentina. E-mail: cjperfumo@fcv.unlp.edu.ar The objectives were to determine the prevalence of fibrinonecrotic enteritis (FNE) on a farrow-to-finish farm of 1,000 sows, to categorize the pathological changes, and to to investigate the lesion associated agents Isospora suis and Clostridium perfringens. Causes of preweaning mortality (PWM) were classified into 8 categories including FNE. Obtained data were evaluated for statistical significance by adjusted Chi-square analysis. Samples of FNE were taken for complementary studies including a PCR technique for genotyping toxin genes of Clostridium perfringens from gut samples fixed in 10% neutral formalin. From 3,153 piglets examined, less than 1% was classified as FNE. FNE prevalence increased progressively from the first to the third week, the last differing statistically from the others. Eighty percent of gut samples with FNE lesions were positive to Isospora suis, when examined by PCR from 9 severe FNE lesions detected 7 positive samples only for a toxin gene, characteristic of C. perfringens type-A.

Abstract in English:

ABSTRACT.- Brito L.G., Regitano L.C.A., Huacca M.E.F., Carrilho E. & Moya Borja G.E. 2007. Genotype characterization of the horn fly Haematobia irritans from different Brazilian geographic regions based on randomly amplified polymorphic DNA (RAPD) analysis. Pesquisa Veterinária Brasileira 27(1):1-5. Laboratório de Sanidade Animal, Embrapa Rondônia, BR 364 Km 5,5, Porto Velho, RO 78900-970, Brazil. E-mail: luciana@cpafro.embrapa.br Blood-sucking diptera are important parasites in bovine production systems, especially regarding confinement conditions. Haematobia irritans, the horn fly, is one of the most troublesome species within bovine production systems, due to the intense stress imposed to the animals. An important aspect while studying the variability within a species is the study of the geographic structure of its populations and, attempting to find out the genetic flow of Brazilian populations of horn fly, the RAPD technique, which is suited for this purpose, has been used. The use of molecular markers generated from RAPD made it possible to identify the geographic origin of samples from different Brazilian geographic regions, as well as to estimate the genotypic flow among the different Brazilian populations of the horn fly.

• Haematobia irritans genetic diversity RAPD-PCR molecular markers

Abstract in Portuguese:

ABSTRACT.- Brito L.G., Regitano L.C.A., Huacca M.E.F., Carrilho E. & Moya Borja G.E. 2007. Genotype characterization of the horn fly Haematobia irritans from different Brazilian geographic regions based on randomly amplified polymorphic DNA (RAPD) analysis. Pesquisa Veterinária Brasileira 27(1):1-5. Laboratório de Sanidade Animal, Embrapa Rondônia, BR 364 Km 5,5, Porto Velho, RO 78900-970, Brazil. E-mail: luciana@cpafro.embrapa.br Blood-sucking diptera are important parasites in bovine production systems, especially regarding confinement conditions. Haematobia irritans, the horn fly, is one of the most troublesome species within bovine production systems, due to the intense stress imposed to the animals. An important aspect while studying the variability within a species is the study of the geographic structure of its populations and, attempting to find out the genetic flow of Brazilian populations of horn fly, the RAPD technique, which is suited for this purpose, has been used. The use of molecular markers generated from RAPD made it possible to identify the geographic origin of samples from different Brazilian geographic regions, as well as to estimate the genotypic flow among the different Brazilian populations of the horn fly.

Abstract in English:

Abstract.- Brocchi M., Ferreira A., Lancellotti M., Stehling E.G., Campos T.A., Nakazato G., Pestana de Castro A.F. & Silveira W.D. 2006. Typing of avian pathogenic Escherichia coli strains by REP-PCR. Pesquisa Veterinária Brasileira 26(2):69-73. Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade de Campinas, Cx. Postal 6109, Campinas, SP 13081-862, Brazil. E-mail: wds@unicamp.br In the present study the repetitive extragenic palindromic (REP) polymerase chain reaction (PCR) technique was used to establish the clonal variability of 49 avian Escherichia coli (APEC) strains isolated from different outbreak cases of septicemia (n=24), swollen head syndrome (n=14) and omphalitis (n=11). Thirty commensal strains isolated from poultry with no signs of these illnesses were used as control strains. The purified DNA of these strains produced electrophoretic profiles ranging from 0 to 15 bands with molecular sizes varying from 100 bp to 6.1 kb, allowing the grouping of the 79 strains into a dendrogram containing 49 REP-types. Although REP-PCR showed good discriminating power it was not able to group the strains either into specific pathogenic classes or to differentiate between pathogenic and non-pathogenic strains. On the contrary, we recently demonstrated that other techniques such as ERIC-PCR and isoenzyme profiles are appropriate to discriminate between commensal and APEC strains and also to group these strains into specific pathogenic classes. In conclusion, REP-PCR seems to be a technique neither efficient nor universal for APEC strains discrimination. However, the population clonal structure obtained with the use of REP-PCR must not be ignored particularly if one takes into account that the APEC pathogenic mechanisms are not completely understood yet.

• Avian Escherichia coli typing REP-PCR.

Abstract in Portuguese:

Abstract.- Brocchi M., Ferreira A., Lancellotti M., Stehling E.G., Campos T.A., Nakazato G., Pestana de Castro A.F. & Silveira W.D. 2006. Typing of avian pathogenic Escherichia coli strains by REP-PCR. Pesquisa Veterinária Brasileira 26(2):69-73. Departamento de Microbiologia e Imunologia, Instituto de Biologia, Universidade de Campinas, Cx. Postal 6109, Campinas, SP 13081-862, Brazil. E-mail: wds@unicamp.br In the present study the repetitive extragenic palindromic (REP) polymerase chain reaction (PCR) technique was used to establish the clonal variability of 49 avian Escherichia coli (APEC) strains isolated from different outbreak cases of septicemia (n=24), swollen head syndrome (n=14) and omphalitis (n=11). Thirty commensal strains isolated from poultry with no signs of these illnesses were used as control strains. The purified DNA of these strains produced electrophoretic profiles ranging from 0 to 15 bands with molecular sizes varying from 100 bp to 6.1 kb, allowing the grouping of the 79 strains into a dendrogram containing 49 REP-types. Although REP-PCR showed good discriminating power it was not able to group the strains either into specific pathogenic classes or to differentiate between pathogenic and non-pathogenic strains. On the contrary, we recently demonstrated that other techniques such as ERIC-PCR and isoenzyme profiles are appropriate to discriminate between commensal and APEC strains and also to group these strains into specific pathogenic classes. In conclusion, REP-PCR seems to be a technique neither efficient nor universal for APEC strains discrimination. However, the population clonal structure obtained with the use of REP-PCR must not be ignored particularly if one takes into account that the APEC pathogenic mechanisms are not completely understood yet.

Abstract in English:

Simionatto S., Lima-Rosa C.A.V., Rubin L.L. & Canal C.W. 2005. [A nested-PCR protocol for detection of the chicken anemia virus.] Um protocolo de “nested-PCR” para detecção do virus da anemia das galinhas. Pesquisa Veterinária Brasileira 25(2):106-110. Laboratório de Virologia, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: claudio.canal@ufrgs.br This paper reports a nested polymerase chain reaction (nested-PCR) protocol for detection of chicken anemia virus (CAV), the causal agent of infectious chicken anemia. For DNA extraction from clinical samples, a method based on guanidine thiocyanate was found more sensitive and practical than other extraction protocols tested. The pair of primers used in the initial PCR targeted a 664 bp fragment on the VP1 gene. The primers for the internal PCR targeted a fragment of 520 bp. The specificity of the primers was evaluated on samples of CAV controlled flocks. Thirty different viruses and bacteria isolated from chickens did not give rise to any amplification product in the assay. The sensitivity of the nested-PCR was determined on serial dilutions of a CAV vaccine. The nested-PCR was more sensitive than a one step PCR and was able to detect at least 0.16 TCID50 of the vaccine strain. In addition, the protocol employed here detected viral DNA from tissues, sera and litter from flocks with or without clinical signs of disease. It is concluded that the nested-PCR protocol described here is more sensitive, faster and less cumbersome than virus isolation in cell culture as a diagnostic technique for detection of CAV.

• Chicken anemia virus CAV molecular diagnosis nested-PCR.

Abstract in Portuguese:

Simionatto S., Lima-Rosa C.A.V., Rubin L.L. & Canal C.W. 2005. [A nested-PCR protocol for detection of the chicken anemia virus.] Um protocolo de “nested-PCR” para detecção do virus da anemia das galinhas. Pesquisa Veterinária Brasileira 25(2):106-110. Laboratório de Virologia, Faculdade de Veterinária, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9090, Porto Alegre, RS 91540-000, Brazil. E-mail: claudio.canal@ufrgs.br This paper reports a nested polymerase chain reaction (nested-PCR) protocol for detection of chicken anemia virus (CAV), the causal agent of infectious chicken anemia. For DNA extraction from clinical samples, a method based on guanidine thiocyanate was found more sensitive and practical than other extraction protocols tested. The pair of primers used in the initial PCR targeted a 664 bp fragment on the VP1 gene. The primers for the internal PCR targeted a fragment of 520 bp. The specificity of the primers was evaluated on samples of CAV controlled flocks. Thirty different viruses and bacteria isolated from chickens did not give rise to any amplification product in the assay. The sensitivity of the nested-PCR was determined on serial dilutions of a CAV vaccine. The nested-PCR was more sensitive than a one step PCR and was able to detect at least 0.16 TCID50 of the vaccine strain. In addition, the protocol employed here detected viral DNA from tissues, sera and litter from flocks with or without clinical signs of disease. It is concluded that the nested-PCR protocol described here is more sensitive, faster and less cumbersome than virus isolation in cell culture as a diagnostic technique for detection of CAV.

Abstract in English:

Penatti M.P.A., Silva A.S., Valadares G.F. & Leite D.S. 2005. Occurrence of F42 colonization factor in Escherichia coli strains isolated from piglets with diarrhea. Pesquisa Veterinária Brasileira 25(1):31-33. Depto Microbiologia e Imunologia, Instituto de Biologia, Unicamp, Campinas, SP 13081-970, Brazil. E-mail: domingos@unicamp.br The objective of this study was to determine the presence of the colonization factor F42 in 168 strains of Escherichia coli isolated from diarrheic stools of newborn piglets. The presence of F42 in 12 (7.1%) strains was detected with the agglutination test. Through the Polymerase Chain Reaction (PCR) of F42 positive strains, gene encoding enterotoxins (ST-I, ST-II, LT-I and LT-II) were detected. The finding of ST-I/ST-II genes in 50% of the strains, ST-I (16%) and ST-II (25%) indicates a strong association of FC F42 with heat-stable enterotoxins (91%). In contrast, the thermolabile enterotoxin (LT-I and LT-II) genes were not detected. Serogroups of F42 positive strains were determined, serogroup O8 being the most prevalent (41,7%). Other serogroups, as there are O9, O11, O18, O32, O35, O98 and O101, were also identified. Thus, FC F42 was confirmed as an additional factor of virulence in the pathogenesis of porcine colibacillosis.

• Escherichia coli F42 piglets fimbriae diarrhea PCR.

Abstract in Portuguese:

Penatti M.P.A., Silva A.S., Valadares G.F. & Leite D.S. 2005. Occurrence of F42 colonization factor in Escherichia coli strains isolated from piglets with diarrhea. Pesquisa Veterinária Brasileira 25(1):31-33. Depto Microbiologia e Imunologia, Instituto de Biologia, Unicamp, Campinas, SP 13081-970, Brazil. E-mail: domingos@unicamp.br The objective of this study was to determine the presence of the colonization factor F42 in 168 strains of Escherichia coli isolated from diarrheic stools of newborn piglets. The presence of F42 in 12 (7.1%) strains was detected with the agglutination test. Through the Polymerase Chain Reaction (PCR) of F42 positive strains, gene encoding enterotoxins (ST-I, ST-II, LT-I and LT-II) were detected. The finding of ST-I/ST-II genes in 50% of the strains, ST-I (16%) and ST-II (25%) indicates a strong association of FC F42 with heat-stable enterotoxins (91%). In contrast, the thermolabile enterotoxin (LT-I and LT-II) genes were not detected. Serogroups of F42 positive strains were determined, serogroup O8 being the most prevalent (41,7%). Other serogroups, as there are O9, O11, O18, O32, O35, O98 and O101, were also identified. Thus, FC F42 was confirmed as an additional factor of virulence in the pathogenesis of porcine colibacillosis.

Abstract in English:

França T.N., Peixoto P.V., Brito M.F., Driemeier D., Mores N. & Zanella J. 2005. [Outbreak of Circovirosis (Porcine Postweaning Multisystemic Wasting Syndrome) in the state of Rio de Janeiro, Brazil.] Surto de Circovirose (Síndrome Definhante Multissistêmica de Suínos Desmamados) no estado do Rio de Janeiro. Pesquisa Veterinária Brasileira 25(1):39-53. Universidade Estácio de Sá, Curso de Medicina Veterinária, Disciplina de Anatomia Patológica, Estrada Boca do Mato 850, Vargem Pequena, RJ 22783-320, Brazil. E-mail: ticianaf@uol.com.br The first outbreak of Postweaning Multisystemic Wasting Syndrome (PMWS) in swine, which occurred in southeastern Brazil, in the state of Rio de Janeiro, is described. The disease, which affects mainly weaned about 4 month-old pigs, caused the death of at least 14 animals. The property, where the outbreak occurred, had inadequate sanitary and management conditions. Clinically the disease was characterized by wasting, poor development, cough, tachypnoea, dispnoea, diarrhoea, ataxia, tremors after stimulation, decubitus and convulsions. The course of the disease was acute or subacute. The most important post-mortem findings were enlarged lymphnodes, non-collapsed lungs, with consolidated areas mainly in the cranial lobes. Histological lesions consisted mainly of lymphohistiocytic infiltration with multinucleate giant cells in lymph nodes, spleen, Peyer’s patches, kidney, lung and liver, depletion or lymphoid hyperplasia, as well as lymphohistiocytic interstitial pneumonia and areas of secondary bronchopneumonia. The diagnosis was established through observations of the symptoms and typical lesions, and was confirmed by immunohistochemical examination and PCR. The objective of this study was to characterize the epidemiological, clinical and pathological aspects of the outbreak of PMWS, because of the severe direct or indirect economical losses caused by the disease to the world pig industry.

• Postweaning multisystemic wasting syndrome porcine circovirus type 2 pathology immunohistochemistry PCR.

Abstract in Portuguese:

França T.N., Peixoto P.V., Brito M.F., Driemeier D., Mores N. & Zanella J. 2005. [Outbreak of Circovirosis (Porcine Postweaning Multisystemic Wasting Syndrome) in the state of Rio de Janeiro, Brazil.] Surto de Circovirose (Síndrome Definhante Multissistêmica de Suínos Desmamados) no estado do Rio de Janeiro. Pesquisa Veterinária Brasileira 25(1):39-53. Universidade Estácio de Sá, Curso de Medicina Veterinária, Disciplina de Anatomia Patológica, Estrada Boca do Mato 850, Vargem Pequena, RJ 22783-320, Brazil. E-mail: ticianaf@uol.com.br The first outbreak of Postweaning Multisystemic Wasting Syndrome (PMWS) in swine, which occurred in southeastern Brazil, in the state of Rio de Janeiro, is described. The disease, which affects mainly weaned about 4 month-old pigs, caused the death of at least 14 animals. The property, where the outbreak occurred, had inadequate sanitary and management conditions. Clinically the disease was characterized by wasting, poor development, cough, tachypnoea, dispnoea, diarrhoea, ataxia, tremors after stimulation, decubitus and convulsions. The course of the disease was acute or subacute. The most important post-mortem findings were enlarged lymphnodes, non-collapsed lungs, with consolidated areas mainly in the cranial lobes. Histological lesions consisted mainly of lymphohistiocytic infiltration with multinucleate giant cells in lymph nodes, spleen, Peyer’s patches, kidney, lung and liver, depletion or lymphoid hyperplasia, as well as lymphohistiocytic interstitial pneumonia and areas of secondary bronchopneumonia. The diagnosis was established through observations of the symptoms and typical lesions, and was confirmed by immunohistochemical examination and PCR. The objective of this study was to characterize the epidemiological, clinical and pathological aspects of the outbreak of PMWS, because of the severe direct or indirect economical losses caused by the disease to the world pig industry.

Abstract in English:

Beltrão N., Furian T.Q., Leão J.A., Pereira R.A., Moraes L.B. & Canal C.W. 2004. [Detection of infectious laryngotracheitis virus in chickens in Brazil.] Detecção do vírus da laringotraqueíte das galinhas no Brasil. Pesquisa Veterinária Brasileira 24(2):85-88. Centro de Diagnóstico e Pesquisa em Patologia Aviária (CDPA), Faculdade de Veterinária, UFRGS, Porto Alegre, RS 91540-000, Brazil. E-mail: nilzaneb@hotmail.com A study was carried out in search for evidences of infectious laryngotracheitis virus (ILTV) infections in some Brazilian chicken flocks. Tracheal tissues and swabs were collected from 10 different flocks of layers and broilers displaying respiratory signs of disease. Samples were processes for virus isolation in embryonated eggs and the membranes examined by histopathology. In addition, specimens were examined by polymerase chain reaction (PCR). Three flocks had ILTV positive chickens by virus isolation and PCR. These results confirm the occurrence of ILTV in chickens in Brazil.

• Infectious laryngotracheitis virus PCR virus isolation avian pathology.

Abstract in Portuguese:

Beltrão N., Furian T.Q., Leão J.A., Pereira R.A., Moraes L.B. & Canal C.W. 2004. [Detection of infectious laryngotracheitis virus in chickens in Brazil.] Detecção do vírus da laringotraqueíte das galinhas no Brasil. Pesquisa Veterinária Brasileira 24(2):85-88. Centro de Diagnóstico e Pesquisa em Patologia Aviária (CDPA), Faculdade de Veterinária, UFRGS, Porto Alegre, RS 91540-000, Brazil. E-mail: nilzaneb@hotmail.com A study was carried out in search for evidences of infectious laryngotracheitis virus (ILTV) infections in some Brazilian chicken flocks. Tracheal tissues and swabs were collected from 10 different flocks of layers and broilers displaying respiratory signs of disease. Samples were processes for virus isolation in embryonated eggs and the membranes examined by histopathology. In addition, specimens were examined by polymerase chain reaction (PCR). Three flocks had ILTV positive chickens by virus isolation and PCR. These results confirm the occurrence of ILTV in chickens in Brazil.

Abstract in English:

ABSTRACT.- Caldas A.P.F., Leal E.S., Silva E.F.A. & Ravazzolo A.P. [Detection of feline immunodeficiency provirus in domestic cats by polymerase chain reaction.] Detecção do provírus da Imunodeficiência Felina em gatos domésticos pela técnica de Reação em Cadeia da Polimerase. Pesquisa Veterinária Brasileira 20(1):20-25. Centro de Biotecnologia/Faculdade de Veterinária, UFRGS, Av. Bento Gonçalves 9500, Porto Alegre, RS 91501-970, Brazil. Feline immunodeficiencyvirus (FIV) infection of domestic cats is one of the most promising animal models for the infection by the human immunodeficiency virus (HIV) which causes acquired immunodeficiency syndrome (AIDS). lnfected cats may develop a disease similar to that observed in AIDS patients, with increased susceptibility to opportunistic infections. Ln this study we used the polymerase chain reaction (PCR) to detect proviral DNA of feline immunodeficiency virus on the blood and tissue samples from cats with a clinical diagnosis of immunodeficiency. The PCR primers were used to amplify the gag gene, which is conserved among different isolates. From 40 samples analyzed, 15 were positive and 4 of them were submitted to hybridization to confirm the specificity of the amplified fragments. These results confirm the presence of FIV in domestic cats in Rio Grande do Sul, Brazil.

• Feline immunodeficiency virus FIV polymerase chain reaction PCR Vírus da Imunodeficiência Felina Reação em Cadeia da Polimerase.

Abstract in Portuguese:

SINOPSE.- Caldas A.P.F., Leal E.S., Silva E.F.A. & Ravazzolo A.P. [Detection of feline immunodeficiency provirus in domestic cats by polymerase chain reaction.] Detecção do provírus da Imunodeficiência Felina em gatos domésticos pela técnica de Reação em Cadeia da Polimerase. Pesquisa Veterinária Brasileira 20(1):20-25. Centro de Biotecnologia/Faculdade de Veterinária, UFRGS, Av. Bento Gonçalves 9500, Porto Alegre, RS 91501-970, Brazil. A infecção de gatos domésticos pelo Vírus da Imunodeficiência Felina (FIV) é um dos modelos mais promissores para o estudo da infecção pelo vírus da imunodeficiência humana (HIV) que causa a Síndrome de Imunodeficiência Adquirida (AIDS). O FIV causa, em gatos, uma enfermidade similar àquela observada em pacientes com AIDS, sobretudo no que diz respeito ao aumento da susceptibilidade a infecções oportunistas. No presente estudo, utilizou-se a Reação em Cadeia da Polimerase (PCR), com o objetivo de detectar o provírus do FIV em gatos com sinais clínicos de imunodeficiência. O fragmento de DNA escolhido como alvo para amplificação situa-se no gene gag do lentivírus felino, o qual é conservado entre as diferentes amostras do vírus. O DNA utilizado foi extraído a partir de amostras de sangue e de tecidos de animais com suspeita clínica de imunodeficiência. Das 40 amostras analisadas, 15 foram positivas, das quais 4 foram submetidas à hibridização, confirmando a especificidade dos fragmentos amplificados. Esses resultados demonstram a presença do FIV na população de gatos domésticos do Rio Grande do Sul, Brasil.

Abstract in English:

ABSTRACT.- González E.T., Norimine J., Valera A.R., Travería G., Oliva G.A. & Etcheverrigaray M.E. 1999. A rapid and sensitive diagnosis of bovine leukaemia virus infection using the nested shuttle polyrnerase chain reaction. [Diagnóstico rápido e sensível da infecção com o vírus da Leucemia Bovina através de Shuttle Nested Polyrnerase Chain Reaction.] Pesquisa Veterinária Brasileira 19(2):63-67. Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118, 1900 La Plata, Argentina. Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). In Argentina, where a program to eradicate EBL has been introduced, sensitive and reliable diagnosis has attained high priority. Although the importance of the agar gel immunodiffusiontest remains unchanged for routine work, an additional diagnostic technique is necessary to confirm cases of sera with equivocal results or of calves carrying maternal antibodies. Utilizing a nested shuttle polymerase chain reaction, the provira) DNA was detected from cows experimentally infected with as little as 5 ml of whole blood from BLV seropositive cows that were nonetheless normal in haematological terms. It proved to be a very sensitive technique, since it rapidly revealed the presence of the proviras, frequently at 2 weeks postinoculation and using a two-round procedure of nested PCR taking only 3 hours. Additionally, the primers used flanked a portion of the viral genome often employed to differentiate BLV type applying BamHI digestion. It is concluded that this method might offer a highly promising diagnostic tool for BLV infection.

• Bovine Ieukaemia virus diagnosis Nested-PCR Leucose bovina diagnóstico.

Abstract in Portuguese:

RESUMO.- González E.T., Norimine J., Valera A.R., Travería G., Oliva G.A. & Etcheverrigaray M.E. 1999. A rapid and sensitive diagnosis of bovine leukaemia virus infection using the nested shuttle polyrnerase chain reaction. [Diagnóstico rápido e sensível da infecção com o vírus da Leucemia Bovina através de Shuttle Nested Polyrnerase Chain Reaction.] Pesquisa Veterinária Brasileira 19(2):63-67. Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata, 60 y 118, 1900 La Plata, Argentina. Bovine leukaemia virus (BLV) is the causative agent of enzootic bovine leukosis (EBL). O Vírus da leucemia bovina (BLV) é o agente causal da Leucose Enzoótica Bovina (EBL). Na Argentina, iniciou-se um programa de erradicação da EBL. Neste estágio, é prioritário possuir uma ferramenta de diagnóstico confiável. Embora seja indiscutível a importância do teste de agar gel imunodifusão, empregado rotineiramente no diagnóstico serológico da EBL, faz-se necessária uma técnica de diagnóstico adicional capaz de confirmar os resultados duvidosos. Foi possivel detectar ADN provira) aplicando Nested-PCR em novilhos experimentalmente infectados com pequenas doses de sangue total (5ml) obtidas de um bovino BLV soropositivo. Esta técnica, cujo procedimento leva 3 horas, demonstrou ser muito sensível, uma vez que foi capaz de detectar a presença do proviras duas semanas após a inoculação. Os primers utilizados são os que detectam uma porção do genoma virai que geralmente é usado para diferenciar os tipos de BLV, utilizando a digestão com BamHI. Sugerimos que este método possa ser um instrumento válido para o diagnóstico precoce da infeção pelo BLv.