Risk factors and molecular typing of Toxoplasma gondii isolated from ostriches (Struthio camelus) from a Brazilian slaughterhouse

Abstract

Toxoplasma gondii has a worldwide distribution with different genotypes reported in animals and humans. The parasite is of great importance to food production and public health, highlighted by the high diversity of hosts, i.e. ostriches. This study aimed to determine the prevalence of T. gondii infection in ostriches from a Brazilian slaughterhouse, the genotype, and the associated risk factors. T. gondii antibodies were detected in 38/344 (11.05%) serum samples using the modified agglutination test using formalin-fixed tachyzoites (MAT-HS); the parasite was isolated from 14/38 (36.84%) ostrich brain samples using the mouse bioassay; and the DNA was detected from 25/38 (65.79%), using PCR. In farms, the water tank was considered the main risk factor (OR=141.87; p-value<0.05), and oocysts were detected in 30% (6/20) in soil of paddocks before animals were slaughtered (1st sampling), and 40% (8/20) one-year after (2nd sampling) using microscopy and PCR. Non-ostrich fecal samples on the ground resulted negative. Bioassay isolation was confirmed by PCR. All PCR positive samples were sequenced and resulted in 100% homology to Toxoplasma gondii repetitive DNA sequence (GenBank access number EF648168-1). These samples were also typed through RFLP-PCR using 11 markers: SAG1, SAG2 (5'-3'SAG2 and alt.SAG2), SAG3, BTUB, GRA6, L358, c22-8, c29-6, PK1, Apico and CS3. Two isolates had a complete genotype, typed from the ostrich tissue. In ostrich samples, the parasite load ranged from 19,043 (TgOsBr1, avirulent) to 54,829 parasitesmL(-1) (TgOsBr2, virulent) using qPCR, whereas soil samples ranged from 11 to 2,275 parasitesmL(-1). Both typed isolates resulted on atypical clones, one previously reported to cause congenital toxoplasmosis in Brazilian patients (TgOsBr1, ToxoDB #206). Thus, these findings support the occurrence of T. gondii in slaughtered ostriches from Brazil, ostriches as sentinel for environmental contamination with T. gondii, the genotypic variability in Brazilian isolates, and the first isolation and genotyping of T. gondii from Brazilian slaughtered ostriches.

Adaptive and genetic evolution of Toxoplasma gondii: a host-parasite interaction

“…The parasite's adaptation to different geographic regions and hosts may contribute to the occurrence of polymorphism. As reported previously, Central America and South America present a wide genetic diversity of T. gondii strains as compared to that in Europe and North America 4 , and may reflect an ancient South American origin for the species 9 . Therefore, there is a high probability that after completion of every new study conducted in South and Central America, a new atypical genotypic profile will be identified 5 .…”

rROP2 from Toxoplasma gondii as a potential vaccine against oocyst shedding in domestic cats

“…The risk of becoming infected depends on culinary habits, including the regular consumption of raw or undercooked meat and living in an environment with a higher risk of oocyst contamination (NAVARRO et al, 1992;DIAS et al, 2005;JONES et al, 2006;SANTOS et al, 2010;SILVA & LANGONI, 2016). Cats play an important role in this process due to their close interactions with human beings where infected cats shed millions of oocysts in their feces that subsequently contaminate the environment (DUBEY, 1995;GARCIA et al, 2007).…”

Toxoplasma gondii and Neospora caninum in farm-reared ostriches (Struthio camelus) in China

“…Toxoplasma gondii is an obligate cyst-forming parasite known to infect many species of warm-blooded animals, including ostrich [ 1 , 2 ]. Infection with T. gondii is usually asymptomatic, but it can cause severe illness in both humans and animals with weakened immune systems, and in the case of pregnancy [ 3 ].…”