Molecular and serological diagnosis of toxoplasmosis: a systematic review and meta-analysis

Toxoplasmosis is an infection of vast worldwide distribution whose etiologic agent is Toxoplasma gondii. This disease can cause problems ranging from mild symptoms to serious conditions, such as encephalitis, miscarriage and blindness. Therefore, it is of utmost importance to perform a diagnosis with reproducible techniques in order to obtain a good prognosis. The aim of this review was to analyze the efficiency of toxoplasmosis diagnostic techniques based on sensitivity and specificity results. Five research platforms in English language were used (Eric, Elsevier, Google Scholar, PubMed and SciELO), which contained data on the diagnosis of toxoplasmosis. The search and selection were performed for studies published prior to June 2021. The search resulted in the inclusion of 13 articles published from 2005 to 2020. The data revealed the use of different samples in the standardization of techniques such as serum, total blood, colostrum and amniotic fluid. The flow cytometry, lateral flow immunoassay and qPCR techniques showed 100% sensitivity, whereas the ELISA, western blotting, qPCR and RE-LAMP techniques achieved 100% specificity. Significantly, the qPCR and LAMP techniques were more accurate when the likelihood ratio was assessed. The meta-analysis identified that ISAGA and western blotting have low sensitivity values and LIASON, ELFA and ELISA, using a silica bioconjugate, also have low specificity values. It was noted that a wide range of methods have high values of sensitivity and specificity. Therefore, the choice of the method will be based on the conditions and its financial viability

Molecular characterization and epidemiology of Toxoplasma gondii isolates from free-range chickens in the southwest region of Goiás: new genotypes

Abstract The purpose of this study was to isolate Toxoplasma gondii from tissues of free-range chickens in the southwestern region of Goiás, to detect and molecularly characterize the genetic material of the parasite, and to determine the seroprevalence of the protozoan parasite in these animals. A seroprevalence of T. gondii antibodies of 76% (19/25) was found among the chickens, while genetic material from their tissues was detected in 56% (14/25). A total of 14 isolates was obtained in the bioassay, ten of which were considered acute, eight were considered isolates of high virulence lethal to mice, and four of low virulence, considered non-lethal but with the ability to chronify the infection. Seven of the ten isolates showed significant morphometric differences from the RH strain, in terms of nucleus-complex-apical distance, length and width. Genotyping of the acute isolates was performed by RFLP-PCR, using 11 genetic markers: SAG1, SAG2 (3’SAG2 and 5’SAG2), alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and APICO. The results were compared and classified according to the genotypes listed on the ToxoDB Platform, where different profiles were observed indicating the presence of two known genotypes (#7 and #63) and five new genotypes (NEW 3, NEW4, NEW5, NEW6, NEW 7). The results showed high seroprevalence, isolation rate, molecular detection and genotypic variations of T. gondii in free-range chickens in the southwestern region of Goiás

Copro-PCR do gene B1 para diagnóstico de Toxoplasma gondii em fezes de gatos domésticos

Toxoplasma gondii é um parasita intracelular obrigatório que possui um ciclo de vida heteroxênico, tendo como hospedeiro definitivo os felinos, fato que culmina na manutenção do ciclo de vida parasitário. O objetivo deste estudo foi determinar a prevalência de Toxoplasma gondii em fezes de gatos por meio da Copro-PCR, bem como avaliar a frequência de positividade entre gatos errantes e domiciliados, machos e fêmeas e castrados e não castrados. Para tal, foram coletadas 120 amostras fecais de gatos que, posteriormente, foram submetidas à sedimentação espontânea. Após 24 horas extraiu-se o DNA das amostras com um kit comercial, com adaptações. Após a extração, realizou-se a PCR com os primers que amplificam o gene B1, seguida da eletroforese em gel de poliacrilamida a 6%. Foi possível obter uma prevalência para T. gondii de 14,1% (17/120) na Copro-PCR ao passo que o Exame Parasitológico de Fezes não detectou nenhuma amostra positiva.  Além disso, os gatos errantes obtiveram maior frequência de positividade quando comparado aos domiciliados. Não houve diferença significativa em relação ao sexo e aos animais castrados ou não castrados. Foi possível concluir que a copro-PCR do Gene B1 utilizada na detecção de T. gondii possui uma alta sensibilidade, detectando até mesmo amostras negativas no Exame Parasitológico de Fezes e que os gatos errantes possuem maior probabilidade de se infectarem com T. gondii do que os domiciliados