Distúrbios reprodutivos em cabras experimentalmente infectadas por Toxoplasma gondii / Reproductive disorders in does experimentally infected by Toxoplasma gondii

Objetivou-se descrever os distúrbios reprodutivos associados à infecção experimental por Toxoplasma gondii através da inseminação artificial com sêmen contaminado em quatro cabras no estágio crônico da infecção. As características do trato reprodutor foram avaliadas através de ultrassonografia transretal, visando o diagnóstico gestacional ou de desordens reprodutivas, após a infecção experimental. Ao final do experimento, os animais foram necropsiados e avaliações histopatológicas e PCR foram realizados. Dentre os animais infectados que exibiram mortalidade embrionária, duas apresentaram anestro e duas apresentaram repetição de estro, sendo que destas uma apresentou intervalos entre estros reduzido (sete dias) e outra em intervalo regular (21 dias). Todavia, ambas foram submetidas a monta natural durante os estros naturais subsequentes e não foi confirmada gestação até o final do experimento (90 dias). Duas cabras exibiram alterações nos exames de ultrassonografia, sendo identificadas um cisto ovariano, e uma hidrossalpinge, ambas confirmadas no exame post-mortem. As principais lesões microscópicas nesse grupo foram infiltração neutrofílica dos pulmões, glomerulonefrite intersticial e infiltração neutrofílica do fígado. O DNA de T. gondii foi encontrado nos órgãos (coração e cérebro) de três cabras. Em conclusão, cabras infectadas com sêmen contendo T. gondii no momento da inseminação artificial apresentam distúrbios reprodutivos na fase crônica da infecção que podem estar associados à toxoplasmose.

The aim of this study was to describe the reproductive disorders related to experimental infection by artificial insemination with semen contaminated with Toxoplasma gondii of four goats in the chronic phase of the infection. In the end of the study, the does were submitted to necropsy, and PCR and histopathological evaluations were performed. Among infected does that exhibited embryonic loss, two were in anestrus and two exhibited repeated estrus. One of the latter animals exhibited clinical signs of estrus at seven-day intervals, whereas the other had a 21-day estrous cycle. However, both does were naturally mated on subsequent natural estrous and were not able to get pregnant until the end of the experiment (90 d). Two of the goats exhibited abnormalities in the ultrasound examinations, one of which was an ovarian cyst, while the other was a hydrosalpinx, both of which were confirmed in the post-mortem examination. The main microscopic injuries in this group were neutrophilic infiltration of the lungs, interstitial glomerulonephritis and neutrophilic infiltration of the liver. T. gondii DNA was found in the organs (heart and brain) of three does. In conclusion, does infected with Toxoplasma gondii in semen at the time of artificial insemination display reproductive disorders in the chronic phase of infection that might be associated with toxoplasmosis.

Toxoplasma gondii diagnosis in ovine aborted fetuses and stillborns in the State of Pernambuco, Brazil.

The aim of this research was to study the contribution of Toxoplasma gondii to reproductive failure using nested PCR and histopathological examination of fetuses, stillborns and placentas. We examined 245 organs of fetuses and 28 placentas from 35 abortions and stillborns from naturally occurring miscarriages in sheep in the State of Pernambuco, Brazil. At necropsy, fragments of brain, cerebellum, medulla, lung, heart, spleen, liver and placenta were taken for nested PCR and histopathological tests. Pathological examination revealed macroscopic lesions, suggesting T. gondii infection in 5/35 (14.3%) of the placentas. The histopathological examination revealed no lesions characteristic of toxoplasmosis in the organs investigated. In the five placentas, lesions consistent with toxoplasmosis were observed as an inflammatory non-suppurative infiltrate, along with multiple necrosis and mineralization. Nested PCR showed three aborted fetuses and two stillborns (14.3%) to test positive for T. gondii, with DNA amplification in all organs and the placenta, especially the heart and the placenta, which are the tissues of choice. This study substantiates the theory that T. gondii is involved in miscarriages and stillbirths and in the placentas of naturally infected sheep in Brazil. Such findings have not previously been described in the national literature.

Toxoplasma gondii: effect of maternal infection in the development of lymphoid organs of BALB/c neonates.

Toxoplasmosis is one of the worldwide parasitic zoonoses. Alterations in the lymphopoietic system are still poorly studied. We analyzed lymphoid organs of BALB/c mice neonates from Toxoplasma gondii-intraperitoneally-infected mothers on 19th day of gestation, with 30 tachyzoites of strain RH. Normal non-infected pregnant females were used as controls. At 7 days after birth, animals were classified as neonates from infected (NIM) and neonates from non-infected mothers (NNIM). Weight of the thymus and number of thymic cells in NIM were decreased, percentage of apoptosis was significantly increased. Decrease in lymphocytes and monocytes and an increase of plasma cells were observed in bone marrow of NIM. Peripheral blood of NIM showed an increase of monocytes and neutrophils and a decrease in lymphocytes. Infection of the mother during the last day of gestation provokes in the neonates changes in the lymphoid organs that could explain survival of 75% of them.

Transplacental toxoplasmosis in naturally-infected white-tailed deer: Isolation and genetic characterisation of Toxoplasma gondii from foetuses of different gestational ages.

Clinical toxoplasmosis is most severe in congenitally-infected hosts. In humans, transmission of Toxoplasma gondii from the mother to the foetus is considered to be most efficient during the last trimester of pregnancy but clinical congenital toxoplasmosis is more severe if transmission occurs during the first trimester. However, there are no data on the rate of congenital transmission of T. gondii with respect to gestational age in any host during natural infection. In the present study, attempts were made to isolate T. gondii by bioassay in mice inoculated with tissues from foetuses of 88 naturally-exposed white-tailed deer from Iowa and Minnesota. Viable T. gondii was isolated from foetuses of six of 61 deer in early pregnancy (45-85 days of gestation) from Iowa and foetuses of nine of 27 deer from Minnesota in mid-gestation (130-150 days) of a gestational period of 7 months. The 15 T. gondii isolates obtained from foetal deer were PCR-restriction fragment length polymorphism genotyped using polymorphisms at 10 nuclear markers including SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and an apicoplast marker, Apico. Five genotypes were revealed, including the clonal Type II and III lineages, and three non-clonal genotypes. DNA sequencing analysis of representative isolates at loci SAG2, c22-8, L358 and PK1 revealed that the three non-clonal genotypes are closely related to the clonal Type I, II and III lineages. It is very likely that these non-clonal genotypes were derived from genetic crosses among the three clonal Type I, II and III lineages. The most common genotype was Type II, commonly found in humans in North America and Europe, suggesting the possible link of transmission from game animals to humans.

Prenatal diagnosis and treatment of congenital Toxoplasma gondii infections: an experimental study in rhesus monkeys.

The efficacy of treatment in fetuses in whom congenital Toxoplasma gondii infection has ben established has been investigated using rhesus monkeys as a model for humans. A polymerase chain reaction has been developed for the detection of Toxoplasma gondii. Using this polymerase chain reaction congenital infection can be established within 2 days of receiving an amniotic fluid sample. The polymerase chain reaction has subsequently been used to monitor the effect of treatment on fetal infection. The results show that early treatment with the combination of pyrimethamine and sulfadiazine was clearly effective in reducing the number of parasites in the infected fetus. The parasite was no longer detectable in the amniotic fluid 10 to 13 days after treatment was started. Spiramycin, on the other hand, has to be administered for at least 3 weeks to achieve the same effect. Moreover, pharmacokinetic studies revealed that spiramycin does not reach the brain. Pyrimethamine and sulfadiazine are able to pass the blood-brain barrier. Pyrimethamine appears to accumulate in the brain tissue and reaches concentrations which are also effective in vitro.

Simple technique for the direct isolation of toxoplasma tissue cysts from fetal ovine brain.

A simple technique is described for the isolation of Toxoplasma gondii tissue cysts from fetal ovine brain by centrifugation on a discontinuous density gradient of 30 per cent and 90 per cent Percoll (colloidal silica solution). Brain samples from 51 aborted ovine fetuses were examined by both the Percoll and mouse inoculation techniques; eight infections were detected by the Percoll technique compared to 12 by mouse inoculation. Possible reasons for this discrepancy and the scope for improving the Percoll technique are discussed.