IgM and IgG as markers of infection transplacentary Neospora caninum in bovine fetuses

O objetivo deste estudo foi determinar a ocorrência de anticorpos anti-Neospora caninum em 260 amostras de soro coletadas de fetos bovinos de julho de 2007 a março de 2008, em abatedouro do município de Santa Maria, Rio Grande do Sul, Brasil. Para detecção de anticorpos anti-N. caninum, a técnica de imunofluorescência indireta foi utilizada tanto para a detecção de imunoglobulinas G e M. Amostras com títulos e" 25 foram consideradas positivas. Das 260 amostras testadas, 15% (39/260) foram positivas para anticorpos anti-N. caninum. Destas, em 38 (97,4%) foi detectada a presença de IgG anti-N. caninum e em seis (15,4%) de IgM. Em cinco amostras (12,8%) detectaram-se ambos, IgG e IgM. Os resultados reafirmam a habilidade do N. caninum em determinar infecção fetal. A pesquisa de IgM foi de limitada importância na detecção da infecção via transplacentária em soro fetal bovino.The aim of this study was to determine the occurrence of anti-Neospora caninum antibodies in serum samples collected from 260 bovine fetuses, between July 2007 and March 2008, in an abattoir in the municipality of Santa Maria, Rio Grande do Sul, Brazil. An indirect fluorescent antibody test was used to detect anti-N. caninum immunoglobulins G (IgG) and M (IgM), using a cut-off of 1:25. Considering IgG or IgM detection, 15% (39/260) of the samples tested were found positive. Among the positive samples, 38 (97.4%) were positive for IgG and 6 (15.4%) for IgM. However 5 (12.8%) of it were positive for both IgG and IgM. These results are in agreement with the proven ability of N. caninum to fetal infection. IgM testing was few relevant to detect N. caninum transplacental infection through fetal bovine serum analisys

Prevalence of antibodies and risk factors associated with infection by Toxoplasma gondii in free range chickens of rural area of Santa Maria, Rio Grande do Sul, Brazil

Toxoplasma gondii is an apicomplex protozoan that infects warm-blooded animals and can be considered a major parasite capable of infecting humans. Domestic chickens can be easily infected by protozoa, since they can ingest oocysts found in the soil and are considered good indicators of environmental contamination by T. gondii. The aim of this study was to determine the presence of anti-T. gondii antibodies in free range chickens and to evaluate the risks factors associated with the protozoan in rural area of Santa Maria, RS, Brazil. From March 2013 to February 2014, 597 blood samples from domestic chickens were collected from 74 farms, from nine layers representing each district in the rural area. To evaluate the risk factors, in these farms an epidemiological questionnaire was applied to the residents. Serum samples were tested by indirect immunofluorescence and 49.2% (294/597) were positive for anti-T. gondii antibodies, with titres varying from 16 to 4096. Of the 74 analyzed farms, 63 (85.1%) reported that cats had access to food deposits, with a significant association when positive chickens were present (p = 0.04) and the OR of 4.07. The variable "slaughter of animals" (poultry and cattle) in 51 (68.9%) of the farms was reported the slaughter of cattle and birds in the farm, with significant p value (p = 0.05). Most farms 59 (79.7%) reported the presence of domestic cats, which could be associated with the high seroprevalence found in chickens and the rate of environmental contamination. The high prevalence of antibodies found in this study, in addition to the high frequency of farms with positive cases, suggests a great environmental contamination in the studied districts, thus being a potential risk to human and animal health.Toxoplasma gondii é um protozoário apicomplexa que infecta animais de sangue quente, podendo ser considerado um dos principais parasitas capazes de infectar os seres humanos. Galinhas domésticas podem ser facilmente infectadas por protozoários, uma vez que estas podem ingerir oocistos encontrados no solo, sendo consideradas boas indicadoras de contaminação ambiental por T. gondii. O objetivo deste estudo foi determinar a presença de anticorpos anti-T. gondii em galinhas domésticas criadas extensivamente e avaliar os fatores de risco associados ao protozoário, na zona rural de Santa Maria, RS, Brasil. No período de março de 2013 a fevereiro 2014 foram coletadas 597 amostras de sangue de galinhas domésticas em 74 propriedades, oriundas de nove estratos que representam cada distrito da zona rural. Para avaliar os fatores de risco, nessas propriedades foi aplicado um questionário epidemiológico aos moradores. As amostras de soro foram testadas por imunofluorescência indireta, e 49,2% (294/597) foram positivas para anticorpos anti-T. gondii, com títulos variando de 16 a 4096. Das 74 propriedades analisadas, em 63 (85,1%) houve relatos que os gatos têm acesso ao deposito de alimentos, com associação significativa quando associado à presença de galinhas positivas (p=0,04) e o OR de 4,07. A variável “abate de animais” (aves e bovinos), em 51 (68,9%) das propriedades foi relatado o abate de bovinos e aves na propriedade, com valor de p significativo (p=0,05). A maioria das propriedades 59 (79,7%) foi relatada a presença de gatos domésticos, o que poderia estar associada com a alta soroprevalência encontrada em galinhas e a taxa de contaminação ambiental. A elevada prevalência de anticorpos encontrada neste estudo, além da alta frequência de propriedades com casos positivos, sugere uma grande contaminação ambiental nos distritos pesquisados, sendo assim um risco potencial para a saúde humana e animal.Facultad de Ciencias Veterinaria

Prevalence of antibodies and risk factors associated with infection by Toxoplasma gondii in free range chickens of rural area of Santa Maria, Rio Grande do Sul, Brazil

Toxoplasma gondii is an apicomplex protozoan that infects warm-blooded animals and can be considered a major parasite capable of infecting humans. Domestic chickens can be easily infected by protozoa, since they can ingest oocysts found in the soil and are considered good indicators of environmental contamination by T. gondii. The aim of this study was to determine the presence of anti-T. gondii antibodies in free range chickens and to evaluate the risks factors associated with the protozoan in rural area of Santa Maria, RS, Brazil. From March 2013 to February 2014, 597 blood samples from domestic chickens were collected from 74 farms, from nine layers representing each district in the rural area. To evaluate the risk factors, in these farms an epidemiological questionnaire was applied to the residents. Serum samples were tested by indirect immunofluorescence and 49.2% (294/597) were positive for anti-T. gondii antibodies, with titres varying from 16 to 4096. Of the 74 analyzed farms, 63 (85.1%) reported that cats had access to food deposits, with a significant association when positive chickens were present (p = 0.04) and the OR of 4.07. The variable "slaughter of animals" (poultry and cattle) in 51 (68.9%) of the farms was reported the slaughter of cattle and birds in the farm, with significant p value (p = 0.05). Most farms 59 (79.7%) reported the presence of domestic cats, which could be associated with the high seroprevalence found in chickens and the rate of environmental contamination. The high prevalence of antibodies found in this study, in addition to the high frequency of farms with positive cases, suggests a great environmental contamination in the studied districts, thus being a potential risk to human and animal health.Toxoplasma gondii é um protozoário apicomplexa que infecta animais de sangue quente, podendo ser considerado um dos principais parasitas capazes de infectar os seres humanos. Galinhas domésticas podem ser facilmente infectadas por protozoários, uma vez que estas podem ingerir oocistos encontrados no solo, sendo consideradas boas indicadoras de contaminação ambiental por T. gondii. O objetivo deste estudo foi determinar a presença de anticorpos anti-T. gondii em galinhas domésticas criadas extensivamente e avaliar os fatores de risco associados ao protozoário, na zona rural de Santa Maria, RS, Brasil. No período de março de 2013 a fevereiro 2014 foram coletadas 597 amostras de sangue de galinhas domésticas em 74 propriedades, oriundas de nove estratos que representam cada distrito da zona rural. Para avaliar os fatores de risco, nessas propriedades foi aplicado um questionário epidemiológico aos moradores. As amostras de soro foram testadas por imunofluorescência indireta, e 49,2% (294/597) foram positivas para anticorpos anti-T. gondii, com títulos variando de 16 a 4096. Das 74 propriedades analisadas, em 63 (85,1%) houve relatos que os gatos têm acesso ao deposito de alimentos, com associação significativa quando associado à presença de galinhas positivas (p=0,04) e o OR de 4,07. A variável “abate de animais” (aves e bovinos), em 51 (68,9%) das propriedades foi relatado o abate de bovinos e aves na propriedade, com valor de p significativo (p=0,05). A maioria das propriedades 59 (79,7%) foi relatada a presença de gatos domésticos, o que poderia estar associada com a alta soroprevalência encontrada em galinhas e a taxa de contaminação ambiental. A elevada prevalência de anticorpos encontrada neste estudo, além da alta frequência de propriedades com casos positivos, sugere uma grande contaminação ambiental nos distritos pesquisados, sendo assim um risco potencial para a saúde humana e animal.Facultad de Ciencias Veterinaria

Virulência e multiplicação de isolados de Toxoplasma gondii da região central do Rio Grande do Sul

RESUMO: O protozoário Toxoplasma gondii possui a capacidade de infectar diversas espécies animais, geralmente causando distúrbios reprodutivos. Quatro diferentes isolados de T. gondii - Pains #1 (P1), Pains #2 (P2), Santa Flora #1 (SF1) e Santa Flora #306 (SF306) - foram avaliados, após prévia genotipagem. A capacidade de multiplicação e virulência destes isolados foi analisada in vitro (células Vero) e in vivo (camundongos), sendo realizadas 3 passagens para cada isolado em cada modo avaliado, sendo sempre inoculada a dose de 1x104 taquizoítos em todas as passagens. Os camundongos eram observados diariamente, quanto à presença de sinais clínicos e ocorrência de mortalidade após inoculação dos taquizoítos. Os isolados SF1 e SF306, foram os que apresentaram maior multiplicação média do número total de taquizoítos em cada uma das 3 diferentes passagens realizadas para cada um dos isolados tanto in vitro quanto in vivo. Os primeiros sinais clínicos observados nos camundongos ocorreram entre os dias 5 a 11, após inoculação, com mortalidade acontecendo entre os dias 6 a 15, após inoculação. Assim, a multiplicação parasitária in vitro é semelhante à multiplicação in vivo destes isolados de T. gondii; diferentes isolados com o mesmo genótipo apresentam comportamento de virulência semelhante, caracterizando o isolado SF1 como mais virulento para camundongos

Mapping the sites of latency and reactivation by bovine herpesvirus 5 (BoHV-5) and a thymidine kinase-deleted BoHV-5 in lambs

A thymidine kinase (tk)-deleted bovine herpesvirus 5 (BoHV-5tkΔ) was previously shown to establish latent infection and reactivate - even poorly - in a sheep model (Cadore et al. 2013). As TK-negative alphaherpesviruses are unlike to reactivate in neural tissue, this study investigated the sites of latency and reactivation by this recombinant in lambs. For this, groups of lambs were inoculated intranasally with the parental BoHV-5 strain (SV-507/99) or with the recombinant BoHV-5tkΔ. During latent infection (40 days post-inoculation, pi), the distribution of recombinant virus DNA in neural and non-neural tissues was similar to that of the parental virus. Parental and recombinant virus DNA was consistently detected by PCR in trigeminal ganglia (TGs); frequently in palatine and pharyngeal tonsils and, less frequently in the retropharyngeal lymph nodes. In addition, latent DNA of both viruses was detected in several areas of the brain. After dexamethasone (Dx) administration (day 40pi), the recombinant virus was barely detected in nasal secretions contrasting with marked shedding of the parental virus. In tissues of lambs euthanized at day 3 post-Dx treatment (pDx), reverse-transcription-PCR (RT-PCR) for a late viral mRNA (glycoprotein D gene) demonstrated reactivation of parental virus in neural (TGs) and lymphoid tissues (tonsils, lymph node). In contrast, recombinant virus mRNA was detected only in lymphoid tissues. These results demonstrate that BoHV-5 and the recombinant BoHV-5tkΔ do establish latent infection in neural and non-neural sites. Reactivation of the recombinant BoHV-5tkΔ, however, appeared to occur only in non-neural sites. In anyway, the ability of a tk-deleted strain to reactivate latent infection deserves attention in the context of vaccine safety

A thymidine kinase-deleted bovine herpesvirus 5 establishes latent infection but reactivates poorly in a sheep model

The ability of thymidine kinase (tk)-deleted recombinant bovine herpesvirus 5 (BoHV-5tkΔ) to establish and reactivate latent infection was investigated in lambs. During acute infection, the recombinant virus replicated moderately in the nasal mucosa, yet to lower titers than the parental strain. At day 40 post-infection (pi), latent viral DNA was detected in trigeminal ganglia (TG) of all lambs in both groups. However, the amount of recombinant viral DNA in TGs was lower (9.7-fold less) than that of the parental virus as determined by quantitative real time PCR. Thus, tk deletion had no apparent effect on the frequency of latent infection but reduced colonization of TG. Upon dexamethasone (Dx) administration at day 40 pi, lambs inoculated with parental virus shed infectious virus in nasal secretions, contrasting with lack of infectivity in secretions of lambs inoculated with the recombinant virus. Nevertheless, some nasal swabs from the recombinant virus group were positive for viral DNA by PCR, indicating low levels of reactivation. Thus, BoHV-5 TK activity is not required for establishment of latency, but seems critical for efficient virus reactivation upon Dx treatment

Antibodies against Neospora caninum, Sarcocystis spp. and Toxoplasma gondii detected in buffaloes from Rio Grande do Sul, Brazil

ABSTRACT: The presence of antibodies against Neospora caninum, Sarcocystis spp. and Toxoplasma gondii was evaluated in buffaloes (Bubalus bubalis) from Rio Grande do Sul state (RS), southern Brazil. Serum samples (n=220) were analyzed for antibodies by indirect fluorescent antibody test (IFAT). Antibody presence was considered when the titers were equal or higher than 100 for these protozoa. A total of 60.5% (133/220) buffalo serum samples were positive for at least one of the protozoa evaluated in this study. Antibodies for N. caninum, Sarcocystis spp. and T. gondii were found in 36.4% (80/220), 25.5% (56/220) and 16.8% (37/220) of the buffaloes respectively, indicating a higher frequency of N. caninum infection (p=0.0133). The IFAT is a suitable method to diagnose N. caninum, Sarcocystis spp. and T. gondii infection in buffaloes for detecting IgG antibodies. This study demonstrates the presence of these three protozoa in buffalo herds in RS, Brazil, which may be source of infection to other animals. The high frequency of animals positive for N. caninum is important and could be related to reproductive problems. Additionally, the presence of Sarcocystis spp. and T. gondii in buffaloes can be a possible public health issue