Stray dogs as indicators of Toxoplasma gondii distributed in the environment: the first report across an urban-rural gradient in China.
BACKGROUND
Toxoplasmosis is an important parasitic zoonosis caused by the protozoan Toxoplasma gondii that is distributed world-wide and infects a variety of hosts. However, the prevalence of T. gondii in the environment (such as soil, water and food) is largely unknown. Due to the technical difficulty in oocyst counting directly, an alternative assay using the serologic status of T. gondii in free-living animals, such as stray or free-living dogs, as an indicator, can be used to evaluate environmental contamination indirectly, as they are exposed to the same risk of infection as humans and other animals.


RESULTS
In the present study, 231 stray or free-living dogs across an urban-rural gradient were examined to assess the frequency of T. gondii in the environment. Specific antibodies to T. gondii were found in 93 dogs (40.3%) by enzyme-linked immunosorbent assay (ELISA), and no statistically significant differences were observed in seroprevalences of T. gondii between urban dogs (38.7%) and rural dogs (41%) (p > 0.05).


CONCLUSIONS
A high seroprevalence of T. gondii in stray or free-living dogs in the present study indicates that there would be a wide distribution and a constant infection pressure of T. gondii across an urban-rural gradient, and the oocysts of T. gondii in the environment would be an important source of infection for humans and other animals both in urban and rural areas in China.
Department of Pathogen Biology and Immunology, Laboratory of Infection and Immunity, Xuzhou Medical College, Xuzhou, Jiangsu Province, China.
Chao
C
Yan
Lin-Lin
LL
Fu
Cai-Ling
CL
Yue
Ren-Xian
RX
Tang
Yi-Sheng
YS
Liu
Liang
L
Lv
Na
N
Shi
Ping
P
Zeng
Peng
P
Zhang
Dong-Hui
DH
Wang
Dong-Hui
DH
Zhou
Xing-Quan
XQ
Zhu
Kui-Yang
KY
Zheng
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D002681:China / Q000453:epidemiology; D004283:Dog Diseases / Q000453:epidemiology* / Q000469:parasitology; D004285:Dogs; D004777:Environment; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D012424:Rural Population; D016036:Seroepidemiologic Studies; D014122:Toxoplasma / Q000276:immunology* / Q000302:isolation & purification; D014124:Toxoplasmosis, Animal / Q000453:epidemiology* / Q000469:parasitology; D014505:Urban Population; D015047:Zoonoses
D000913:Antibodies, Protozoan