Resumo
Background: A cutaneous or superficial myxoma is a benign neoplasm of dermal or subcutaneous fibroblast origin. Although rare, it has been previously described in several species, including poultry. It presents as a single node or soft mass with a gelatinous cut surface. Histopathological analysis is essential for diagnosis and to differentiate it from other mesenchymal neoplasms and inflammatory or degenerative processes. Microscopically, it consists of dermal or subcutaneous lobules of plump, stellate, or spindle-shaped, bland-looking cells embedded in a basophilic myxoid matrix. This report describes the pathological findings in a rare case of cutaneous myxoma in a 42-day-old broiler flock. Cases: During ante mortem inspection of a 42-day-old broiler flock at a slaughterhouse under the authority of the Federal Inspection Service (southern Brazil), nodular lesions or encrusted areas with yellow and black areas were observed in the head skin of less than 1% of animals. These lesions, approximately 0.5 cm in diameter, were observed on the comb, in the periocular skin region, and close to the animals' nostrils. During the breeding period, no health or epidemiological events were observed. Fragments of the lesions in the comb and periocular skin were collected and fixed in buffered 10% formalin. The samples were sent to the laboratory, routinely processed, and stained with hematoxylin and eosin and Alcian blue. Microscopically, the lesions consisted of irregular multifocal proliferation of connective tissue showing spindle cells with poorly demarcated borders and scarce cytoplasm in a slightly basophilic myxoid aspect matrix. The adjacent epidermis is compressed due to neoplastic proliferation. No areas of epithelial hyperplasia or inclusion bodies were observed. According to the pathologic description and considering its descriptive epidemiology, our main clinical suspicion was cutaneous fowl pox, a pathology characterized by the appearance of nodules in regions devoid of feathers. However, the microscopic changes observed were compatible with those described for cutaneous myxomas. In addition, the extracellular matrix was positive for Alcian Blue staining, which is an indicator of myxoma. In the present case, the SIF did not report the same macroscopic lesions in other flocks of the same origin. Discussion: Connective tissue tumors, including myxomas, occur considerably less frequently under field conditions. In addition, these neoplasms are more frequent in mature birds and are not usually described in broilers, as observed in this report. The cutaneous myxoma described in broilers is usually a sporadic neoplasm that does not cause zootechnical losses, as observed in the case report. Its etiology is unknown and has been associated with various factors, such as local trauma and foreign bodies. Some fragments of plant material from the breeding environment were microscopically detected in the encrusted areas, which may indicate previous trauma or a foreign body. Myxoma has been associated with avian leukosis virus (ALV) subgroup A, but SIF did not report the same macroscopic lesions in other flocks of the same breeder hen's origin in the present case. Furthermore, sporadic connective tissue tumors associated with the virus occur in mature chickens but not in broilers. Myxoma lesions should be considered in the differential diagnosis of other connective tissue tumors and infectious agents that cause lesions in the skin and subcutaneous tissue.
Assuntos
Animais , Galinhas/lesões , Mixoma/veterinária , Abate de Animais , Neoplasias de Tecido Conjuntivo/veterináriaResumo
Background: Lobular dissecting hepatitis (LDH) is a rare condition of unknown etiology occurring in individuals or in litters of young dogs from some breeds, having poor prognosis and short survival time. Clinically, ascites, weight loss, anorexia, diarrhea and acquired portosystemic shunts are present. Hepatic encephalopathy may also occur. Biochemical blood tests usually show elevated ALT levels. Macroscopically, the liver shows changes in volume, color and regeneration nodules. Histologically, dissection of the parenchyma by connective tissue proliferation leads to disorganization of the liver architecture. The aim of this article is report LDH in two Golden Retriever dogs genetically unrelated.Cases: Two dogs genetically unrelated and of different owners - Golden Retriever breed - were referred to the Veterinary Medical Teaching Hospital of the Universidade Luterana do Brasil (ULBRA). The first case was a female with 17 months of age and the second, brought to examination one year later, was a male with nine months of age. The clinical signs, in both animals were similar, consisting in intense prostration, inapetence, caquexia and ascites for approximately two weeks. The female dog presented also ataxia, convulsion and diarrhea. Blood examination showed, for both dogs, arregenerative anemia, normal levels of alanine aminotransferase (ALT) and elevated levels of alkaline phosphatase. Total serum protein and albumin were also reduced. Both dogs were euthanized due to their critical condition. The necropsy showed similar lesions in both animals: approximately one liter of a free red colored fluid was observed in the abdominal cavity and hepatic changes consisting in pale green color, smooth surface, firm consistence, yellowish nodules at the surface and tissue proliferation at the margins. There was also congestion of the abdominal visceral veins (portal shunts)...
Assuntos
Animais , Cães , Alanina Transaminase/análise , Hepatite Animal/classificação , Hepatite Crônica/veterinária , Cirrose Hepática/veterináriaResumo
Background: Lobular dissecting hepatitis (LDH) is a rare condition of unknown etiology occurring in individuals or in litters of young dogs from some breeds, having poor prognosis and short survival time. Clinically, ascites, weight loss, anorexia, diarrhea and acquired portosystemic shunts are present. Hepatic encephalopathy may also occur. Biochemical blood tests usually show elevated ALT levels. Macroscopically, the liver shows changes in volume, color and regeneration nodules. Histologically, dissection of the parenchyma by connective tissue proliferation leads to disorganization of the liver architecture. The aim of this article is report LDH in two Golden Retriever dogs genetically unrelated.Cases: Two dogs genetically unrelated and of different owners - Golden Retriever breed - were referred to the Veterinary Medical Teaching Hospital of the Universidade Luterana do Brasil (ULBRA). The first case was a female with 17 months of age and the second, brought to examination one year later, was a male with nine months of age. The clinical signs, in both animals were similar, consisting in intense prostration, inapetence, caquexia and ascites for approximately two weeks. The female dog presented also ataxia, convulsion and diarrhea. Blood examination showed, for both dogs, arregenerative anemia, normal levels of alanine aminotransferase (ALT) and elevated levels of alkaline phosphatase. Total serum protein and albumin were also reduced. Both dogs were euthanized due to their critical condition. The necropsy showed similar lesions in both animals: approximately one liter of a free red colored fluid was observed in the abdominal cavity and hepatic changes consisting in pale green color, smooth surface, firm consistence, yellowish nodules at the surface and tissue proliferation at the margins. There was also congestion of the abdominal visceral veins (portal shunts)...(AU)
Assuntos
Animais , Cães , Hepatite Animal/classificação , Hepatite Crônica/veterinária , Alanina Transaminase/análise , Cirrose Hepática/veterináriaResumo
The thymus is a lymphoid organ and usually evaluated for the degree of lymphocyte loss with subjective histological techniques. This study aimed to adapt and to apply of the digital analysis of the lymphoid depletion system (ADDL) in the thymus in order to obtain a more accurate analysis. Glucocorticoid was used to induce immunosuppression in 55 broilers at 21 days of age; other 15 broilers were the control group. After euthanasia of the broilers, postmortem examination was made. Both thymic chains were collected and six lobes were selected for histological examination of the degree of lymphocyte depletion (scores 1 to 5) and for submission to all stages of processing by the ADDL system. The artificial constructed neural networks (ANN) obtained 94.03% of correct classifications. In conclusion, it was possible to adopt objective criteria to evaluate thymic lymphoid depletion with the ADDL system.(AU)
O timo é um órgão linfóide, que é normalmente avaliado para o grau de perda de linfócitos a partir de técnicas histológicas subjetivas. Este trabalho teve como objetivo a adaptação e aplicação do sistema de análise digital de depleção linfóide (ADDL) para o timo, a fim de tornar sua análise mais acurada. Glicocorticóides foram utilizados a fim de induzir imunossupressão em 55 aves de 21 dias de idade. Outras 15 aves formaram o grupo controle. Posteriormente, para cada um dos aves, realizou-se a eutanásia e necropsia. Ambas as cadeias do timo foram coletadas e foram selecionadas seis lóbulos para processamento histológico, análise quanto ao grau de depleção linfocitária (escores de 1-5) e submissão a todas as fases do processamento pelo sistema ADDL. Observou-se que a rede neural artificial (RNA) construída obteve 94,03% de classificações corretas. Em conclusão, foi possível adotar critérios objetivos para avaliar a depleção linfóide tímica utilizando o sistema ADDL.(AU)
Assuntos
Animais , Galinhas/fisiologia , Imunidade Celular/fisiologia , Depleção Linfocítica/veterinária , Linfócitos/fisiologia , Rede Nervosa/fisiologia , Timo/fisiopatologia , Glucocorticoides/análiseResumo
The thymus is a lymphoid organ and usually evaluated for the degree of lymphocyte loss with subjective histological techniques. This study aimed to adapt and to apply of the digital analysis of the lymphoid depletion system (ADDL) in the thymus in order to obtain a more accurate analysis. Glucocorticoid was used to induce immunosuppression in 55 broilers at 21 days of age; other 15 broilers were the control group. After euthanasia of the broilers, postmortem examination was made. Both thymic chains were collected and six lobes were selected for histological examination of the degree of lymphocyte depletion (scores 1 to 5) and for submission to all stages of processing by the ADDL system. The artificial constructed neural networks (ANN) obtained 94.03% of correct classifications. In conclusion, it was possible to adopt objective criteria to evaluate thymic lymphoid depletion with the ADDL system.(AU)
O timo é um órgão linfóide, que é normalmente avaliado para o grau de perda de linfócitos a partir de técnicas histológicas subjetivas. Este trabalho teve como objetivo a adaptação e aplicação do sistema de análise digital de depleção linfóide (ADDL) para o timo, a fim de tornar sua análise mais acurada. Glicocorticóides foram utilizados a fim de induzir imunossupressão em 55 aves de 21 dias de idade. Outras 15 aves formaram o grupo controle. Posteriormente, para cada um dos aves, realizou-se a eutanásia e necropsia. Ambas as cadeias do timo foram coletadas e foram selecionadas seis lóbulos para processamento histológico, análise quanto ao grau de depleção linfocitária (escores de 1-5) e submissão a todas as fases do processamento pelo sistema ADDL. Observou-se que a rede neural artificial (RNA) construída obteve 94,03% de classificações corretas. Em conclusão, foi possível adotar critérios objetivos para avaliar a depleção linfóide tímica utilizando o sistema ADDL.(AU)
Assuntos
Animais , Depleção Linfocítica/veterinária , Linfócitos/fisiologia , Galinhas/fisiologia , Timo/fisiopatologia , Rede Nervosa/fisiologia , Imunidade Celular/fisiologia , Glucocorticoides/análiseResumo
Cytopathology is increasingly utilized in veterinary medicine practice. Advantages include minimal invasion, minor pain to the animal, low cost and few equipment. Disadvantages are high percentage of inconclusive diagnostics and need for training for sampling, preparation and interpretation. This work aimed to evaluate the concordance between cytopathological and histopathological exams performed at the Pathology Laboratory of Veterinary Hospital of ULBRA. The results of cytopathological exams succeeded by histopathology obtained by biopsy or necropsy were analyzed. Eighty-four samples from tumoral masses were studied, 13 (15, 47%) of epithelial origin, 21 (25%) of mesenchymal origin, 23 (27, 38%) of round cells and 27 (32, 14%) of mammary tumors. Among the epithelial tumors, discrepancy occurred only in one case. In mesenchymal tumors, concordance occurred in 76, 19% of the cases. Both exams were concordant in all cases of bone aspirates. Among 23 cases of round cell tumors, 20 presented concordant diagnostics. Mastocytomas were correctly diagnosed by cytopathological exam in all cases but one. The concordance among mammary tumors occurred only in nine of 27 cases (33,33%). It is concluded that the concordance between cytopathological and histopathological exams is high for epithelial and round cell tumors, being low for mesenchymal and mammary tumors.
A citopatologia é cada vez mais utilizada na prática médico-veterinária. As vantagens incluem mínima invasividade, menor sofrimento, baixo custo e necessidade de poucos equipamentos. As desvantagens são alta percentagem de resultados inconclusivos e necessidade de habilidade na coleta, preparo e interpretação. Este trabalho objetivou avaliar a concordância entre os resultados de exames citopatológicos e histopatológicos realizados no Laboratório de Patologia do Hospital Veterinário (Ulbra). Foram analisados resultados de exames citopatológicos sucedidos por histopatológicos de biópsias ou necropsias. 84 amostras de massas tumorais foram estudadas, 13 (15,47 %) de origem epitelial, 21 (25%) de origem mesenquimal, 23 (27,38%) de células redondas e 27 (32,14%) de tumores mamários. Nos de origem epitelial houve discrepância somente em um caso. Nos mesenquimais houve acerto em 76,19% dos casos. O acerto nos casos de aspirados de ossos foi de 100%. Dentre 23 casos de tumores de células redondas, 20 tiveram resultados concordantes. Os mastocitomas foram corretamente diagnosticados, com exceção de um. A concordância nos tumores mamários ocorreu somente em nove de 27 casos (33, 33%). Conclui-se que a concordância entre os dois tipos de exame é alta para os casos de tumores epiteliais e de células redondas, sendo baixa para tumores mesenquimais e mamários.
Assuntos
Animais , Gatos , Cães , Animais de Estimação/fisiologia , Doenças dos Animais/diagnóstico , Neoplasias/diagnóstico , Neoplasias/veterinária , Patologia/métodos , Medicina Veterinária , Neoplasias Mamárias Animais/diagnóstico , Técnicas de Laboratório Clínico/veterináriaResumo
Cytopathology is increasingly utilized in veterinary medicine practice. Advantages include minimal invasion, minor pain to the animal, low cost and few equipment. Disadvantages are high percentage of inconclusive diagnostics and need for training for sampling, preparation and interpretation. This work aimed to evaluate the concordance between cytopathological and histopathological exams performed at the Pathology Laboratory of Veterinary Hospital of ULBRA. The results of cytopathological exams succeeded by histopathology obtained by biopsy or necropsy were analyzed. Eighty-four samples from tumoral masses were studied, 13 (15, 47%) of epithelial origin, 21 (25%) of mesenchymal origin, 23 (27, 38%) of round cells and 27 (32, 14%) of mammary tumors. Among the epithelial tumors, discrepancy occurred only in one case. In mesenchymal tumors, concordance occurred in 76, 19% of the cases. Both exams were concordant in all cases of bone aspirates. Among 23 cases of round cell tumors, 20 presented concordant diagnostics. Mastocytomas were correctly diagnosed by cytopathological exam in all cases but one. The concordance among mammary tumors occurred only in nine of 27 cases (33,33%). It is concluded that the concordance between cytopathological and histopathological exams is high for epithelial and round cell tumors, being low for mesenchymal and mammary tumors.(AU)
A citopatologia é cada vez mais utilizada na prática médico-veterinária. As vantagens incluem mínima invasividade, menor sofrimento, baixo custo e necessidade de poucos equipamentos. As desvantagens são alta percentagem de resultados inconclusivos e necessidade de habilidade na coleta, preparo e interpretação. Este trabalho objetivou avaliar a concordância entre os resultados de exames citopatológicos e histopatológicos realizados no Laboratório de Patologia do Hospital Veterinário (Ulbra). Foram analisados resultados de exames citopatológicos sucedidos por histopatológicos de biópsias ou necropsias. 84 amostras de massas tumorais foram estudadas, 13 (15,47 %) de origem epitelial, 21 (25%) de origem mesenquimal, 23 (27,38%) de células redondas e 27 (32,14%) de tumores mamários. Nos de origem epitelial houve discrepância somente em um caso. Nos mesenquimais houve acerto em 76,19% dos casos. O acerto nos casos de aspirados de ossos foi de 100%. Dentre 23 casos de tumores de células redondas, 20 tiveram resultados concordantes. Os mastocitomas foram corretamente diagnosticados, com exceção de um. A concordância nos tumores mamários ocorreu somente em nove de 27 casos (33, 33%). Conclui-se que a concordância entre os dois tipos de exame é alta para os casos de tumores epiteliais e de células redondas, sendo baixa para tumores mesenquimais e mamários.(AU)
Assuntos
Animais , Gatos , Cães , Neoplasias/diagnóstico , Neoplasias/veterinária , Patologia/métodos , Doenças dos Animais/diagnóstico , Animais de Estimação/fisiologia , Medicina Veterinária , Técnicas de Laboratório Clínico/veterinária , Neoplasias Mamárias Animais/diagnósticoResumo
Background: Infectious laryngotracheitis virus (ILTV) is a member of the family Herpesviridae that has a worldwide distribution, although it is well controlled in areas of intensive production in which periodic outbreaks of the disease occur. ILTV is an important respiratory pathogen of chickens that may cause severe or mild disease in layers and broilers. Severe disease is characterized by respiratory depression, gasping, expectoration of bloody exudate and high mortality. Mild diseased chickens exhibit milder clinical signs and low mortality, and laboratory techniques are mandatory for a final diagnosis. Several techniques have been described for the detection of ILTV, however they have disadvantages that constrains their use in routine diagnosis. Viral multiplication is limited to respiratory tissue, which makes the trachea the ideal site to look for the virus. The purpose of the present study was to develop a sensitive and specific nested Polymerase Chain Reaction (PCR) protocol to detect ILTV DNA directly from tracheal swabs of naturally or experimentally infected chickens. Materials, Methods & Results: The nested-PCR was carried out with two sets of primers selected from a portion of the ILTV thymidine kinase gene. PCR sensitivity was determined by using five-fold serial dilutions of a commercial laryngotracheitis vaccine. PCR was specific as determined by testing related respiratory viruses (pathogens of chickens), ILTV strain, and field isolates. Nested-PCR was 250 times more sensitive than virus isolation (VI). To further validate the ability of this assay to detect ILTV from tracheal swabs, experimentally infected chickens and ILTV suspect cases were examined by VI, PCR, and histopathology. VI and nested-PCR both detected virus in tracheas during all the experimental period. With one exception, all positive samples by VI were also positive by the nested-PCR. However, nested-PCR detected 5 additional positive samples in the end of the experimental period. Through direct histopathology, typical syncytia and inclusion bodies were found in only two samples. In the clinical cases of respiratory illness, VI detected ILTV positive samples in 4 out of the 8 flocks with respiratory illness and histopathological analyses detected 3 flocks but the nested-PCR detected 5 positive fl ocks including those positive by VI and histopathology. Discussion: In the experimental infection, VI and PCR both detected ILTV in the majority of the samples but PCR detected some additional positive samples close to the end of the experimental period. By comparison of the PCR with VI sensitivity, it can be concluded that the protocol here described has a greater advantage over the previously described protocols that afford a direct comparison. Histopathology was the least sensitive test, since viral inclusion bodies and syncytial cells were only observed in two tracheal sections and a possible explanation for this result may be that necrosis and desquamation destroy infected epithelium. In the detection of the virus from clinical cases, the nested-PCR also detected a greater number of positive samples than VI and histopathology. Comparison of the nested-PCR with VI in experimentally infected broilers indicates that the two diagnostic tests are very efficient to detect ILTV in the early time of infection. However, VI tests in late infection may be not as sensitive as the nested-PCR if majority of the ILTV have been inactivated or become latent. Two distinctive sequences were obtained from the positive controls and field isolates. The sequences were specific to ILTV since they had a minimum of 99.5% similarity with previously described strains. The assay described in the present study indicates that the nested-PCR protocol is more sensitive than previously described tests and can replace histopathology and virus isolation with advantage.
Assuntos
Animais , Doenças das Aves Domésticas/virologia , Galinhas/virologia , Reação em Cadeia da Polimerase/veterinária , Herpesvirus Galináceo 1/isolamento & purificação , Infecções por Herpesviridae/veterináriaResumo
Leptospirosis diagnosis was performed through molecular, histopathological and serological tests in 30 culled sows in Rio Grande do Sul, Brazil. The objectives were to compare the efficiency of the three methods, to verify the sensitivity of a PCR methodology using a single primer based on the sequence of a repetitive element of Leptospira interrogans genome, as well as to verify the possible detection of Leptospira in several tissue including the genital tract of sows. The animals were selected based on the microscopic agglutination test in order to have sows with negative and positive results, presenting low and higher serologic titers. The higher frequency (90% of the positive sows) and titers (100 to 800) was observed for L. interrogans serovar bratislava. Leptospira was detected by histopathology in nine sows only, all presenting higher serologic titers (at least 100). A PCR product of 438 bp was observed in all animals (25 kidneys, 24 uterus and 9 oviduct) fragments. Similar PCR product was obtained for DNA from cultures of other pathogenic leptospires, while the pattern observed for the non-pathogenic L. patoc was distinct. No Leptospira spp DNA amplification product was detected in Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella sp, Streptococcus sp and Staphylococcus aureus DNAs obtained from cultures, or in blood DNA samples of two piglets. The molecular system was therefore specific and the most effective to detect low pathogen levels, being able to differentiate pathogenic from non-pathogenic leptospires.(AU)
O diagnóstico da leptospirose foi efetuado através de método molecular, histopatológico e sorológico em 30 matrizes suínas, descartadas, no Rio Grande do Sul, Brasil. Os objetivos foram comparar a eficiência dos 3 métodos, verificar a sensibilidade de um método de PCR que utiliza um primer único baseado na seqüência de um elemento repetitivo do genoma de Leptospira interrogans, bem como verificar a possível detecção de leptospiras em vários tecidos , incluindo o trato genital. Os animais foram selecionados com base no teste de algutinação microscópica para incluir tanto animais negativos como positivos e com baixos e altos títulos sorológicos. As maiores freqüências (90% dos animais positivos) e títulos (100 a 800) foram observados para L. interrogans serovar bratislava. Leptospiras foram detectadas por histopatologia em apenas 9 matrizes, todas com altos títulos (pelo menos 100). Um produto de PCR de 438 bp foi observado em todos os animais (fragmentos de 25 rins, 24 úteros e 9 avidutos). Produtos de PCR similares foram obtidos em DNA de culturas de leptospiras patogênicas, enquanto a não patogênica, L. patoc apresentou um padrão distinto. Nenhum produto de amplificação de DNA de Leptospira spp foi detectado em DNA de culturas de Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa, Salmonella sp, Streptococcus sp and Staphylococus aureus, ou de sangue de dois leitões. O método molecular foi, assim , específico e o mais eficiente para detectar baixos níveis de patógeno, sendo capaz de difernciar leptospiras patogênicas e não patogênicas. (AU)
Assuntos
Animais , Leptospirose/diagnóstico , Leptospira/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Testes de Aglutinação/métodos , Técnicas de Diagnóstico Molecular/métodos , SuínosResumo
Infectious laryngotracheitis virus (ILTV) cause mild to severe respiratory disease in chickens, the purpose of our study being to use Brazilian isolate of ILTV to reproduce ILTV disease in chickens by experimental infection and to compare three diagnostic methods (nested polymerase chain reaction (PCR), virus isolation, histopathology) for detection of ILTV. Forty-eight chickens intratracheally inoculated with ILTV and a further 48 with PBS, showing mild respiratory signs 48 hours post infection (PI) but no signs of infection after day 10 PI. Every 2 days PI, six birds were arbitrarily selected from the control and infected groups, sacrificed and the trachea collected. Both the nested PCR and virus isolation detected the virus from day 2 until day 12 PI. However, at day 12 PI, PCR detected ILTV DNA in 100% of the samples while the virus isolation method detected ILTV in only 33% of the samples. Tracheal histopathology showed intranuclear inclusion bodies on days 8 and 10 PI. The results indicate that the field-isolate of ILTV studied by us is of low pathogenicity and that our nested PCR protocol was able to detect positive samples over a longer infection period than many ILTV diagnostic test already described.
O vírus da laringotraqueíte (VLT) causa de leve a severa doença respiratório em galinhas, o propósito do nosso estudo foi usar um isolado brasileiro de VLT para reproduzir a doença em frangos através da infecção experimental e comparar três métodos de diagnóstico (nested PCR, isolamento viral e histopatologia) para detectar o VLT. Quarenta e oito frangos inoculados intratraquealmente com VLT e outros 48 com PBS, apresentaram sinais respiratórios leves 48 horas após a infecção (PI), mas nenhum sinal após o dia 10 PI. A cada dois dias, seis aves foram selecionados arbitrariamente do controle e do grupo infectado, sacrificados e as traquéias coletadas. Ambos nested PCR e isolamento viral detectaram o vírus do dia 2 até o dia 12 PI. No entanto, no dia 12 PI, a PCR detectou o DNA viral em 100% das amostras enquanto o isolamento viral detectou em somente 33% das amostras. Histopatologia da traquéia revelou corpúsculos de inclusão intranuclear nos dias 8 e 10 PI. Os resultados indicam que o VLT isolado de campo estudado é de baixa patogenicidade e que o protocolo de Nested PCR foi capaz de detectar amostras positivas por um período mais longo da infecção do que muitos testes de diagnósticos descritos.