High Prevalence ofToxoplasma gondiiInfection in Miners: A Case-Control Study in Rural Durango, Mexico.
BACKGROUND
Very little is known about the seroepidemiology of infection with the parasiteToxoplasma gondii (T. gondii)in miners. We determine the association ofT. gondiiinfection and the occupation of miner, and the association of seropositivity forT. gondiiwith the socio-demographic, clinical, work and behavioral characteristics of the miners.


METHODS
Through a case-control study, 125 miners working in Durango State, Mexico and 250 age- and gender-matched non-miner subjects were examined for the presence of anti-T. gondiiIgG and IgM antibodies using enzyme-linked immunoassays. In addition, the presence ofT. gondiiDNA in miners was determined using polymerase chain reaction. Bivariate and multivariate analyses were used to determine the association of socio-demographic, work, clinical and behavioral characteristics of miners withT. gondiiinfection.


RESULTS
Anti-T. gondiiIgG antibodies were detected in 75 (60.0%) of 125 miners and in 55 (22.0%) of 250 controls (odds ratio (OR) = 5.31; 95% confidence interval (CI): 3.33 - 8.47; P < 0.001). Among IgG seropositive subjects, the frequency of anti-T. gondiiIgM antibodies was significantly higher in miners (39/75, 52%) than in controls (8/55, 14.5%) (P < 0.001). AllT. gondiiseropositive miners referred themselves as healthy. Multivariate analysis of socio-demographic, housing, and behavioral characteristics of miners showed thatT. gondiiseropositivity was positively associated with being born in Durango State (OR = 3.44; 95% CI: 1.09 - 10.7; P = 0.03), consumption of boar meat (OR = 5.53; 95% CI: 1.49 - 20.3; P = 0.01), living in an overcrowded home (OR = 5.83; 95% CI: 1.49 - 22.8; P = 0.01), and was negatively associated with cleaning cat excrement (OR = 0.33; 95% CI: 0.11 - 0.90; P = 0.03) and consuming goat meat (OR = 0.16; 95% CI: 0.03 - 0.76; P = 0.02).


CONCLUSIONS
Surprisingly, our results indicate that miners represent a risk group forT. gondiiinfection. This is the first age- and gender-matched case-control study on the association ofT. gondiiinfection and the occupation of miner. Further studies to identify the exact cause of high seropositivity in miners in rural Durango are needed.
Biomedical Research Laboratory, Faculty of Medicine and Nutrition, Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Cosme
C
Alvarado-Esquivel
Secretaria de Salud, Avenida Cuauhtemoc 225 norte, 34000 Durango, Dgo, Mexico.
Sandy Janet
SJ
Pacheco-Vega
Institute for Scientific Research "Dr. Roberto Rivera-Damm", Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Jesus
J
Hernandez-Tinoco
Biomedical Research Laboratory, Faculty of Medicine and Nutrition, Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Luis Omar
LO
Berumen-Segovia
Institute for Scientific Research "Dr. Roberto Rivera-Damm", Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Luis Francisco
LF
Sanchez-Anguiano
Institute for Scientific Research "Dr. Roberto Rivera-Damm", Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Sergio
S
Estrada-Martinez
Institute for Scientific Research "Dr. Roberto Rivera-Damm", Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Ada Agustina
AA
Sandoval-Carrillo
Institute for Scientific Research "Dr. Roberto Rivera-Damm", Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Jose Manuel
JM
Salas-Pacheco
Institute for Microbiology and Hygiene, Campus Benjamin Franklin, Charite Medical School, Hindenburgdamm 27, D-12203 Berlin, Germany; Current address: Medical and Scientific Affairs, Roche Molecular Systems, Pleasanton, CA 94588, USA.
Oliver
O
Liesenfeld
Institute for Scientific Research "Dr. Roberto Rivera-Damm", Juarez University of Durango State, Avenida Universidad S/N, 34000 Durango, Mexico.
Elizabeth Irasema
EI
Antuna-Salcido
Case-control study; Epidemiology; Infection; Mexico; Miners; Seroprevalence; Toxoplasma gondii