The local public health authorities reported nine cases of chikungunya in Mexico in 2019, none of which occurred in Guerrero, a coastal state in the southwest. To test the hypothesis that chikungunya is grossly underreported in Mexico, acute sera were collected from 639 febrile patients from low-income households in Guerrero in 2019 and serologically assayed for chikungunya virus (CHIKV). Analysis of the sera by plaque reduction neutralization test revealed that 181 (28.3%) patients were seropositive for CHIKV. To identify patients with acute CHIKV infections, a subset of sera samples were tested for CHIKV-specific IgM by ELISA. Sera samples from 21 of 189 (11.1%) patients were positive. These patients met the chikungunya case definition established by the WHO. In conclusion, we provide evidence that CHIKV remains an important public health problem in Mexico and that the true number of cases is severely underestimated.
Address correspondence to Bradley J. Blitvich, 2116 Veterinary Medicine, Iowa State University, 2116 Veterinary Medicine Building, Ames, IA 50011. E-mail: email@example.com
Financial support: This study was supported by a postdoctoral scholarship from the from the Consejo Nacional de Ciencia y Tecnología of Mexico (scholarship no. 406531) and intramural funds provided by the College of Veterinary Medicine at Iowa State University.
Authors’ addresses: Daniel Nunez-Avellaneda, Chandra Tangudu, and Bradley J. Blitvich, Veterinary Microbiology & Preventive Medicine, Iowa State University, Ames, IA, E-mails: firstname.lastname@example.org, email@example.com, and firstname.lastname@example.org. Jacqueline Barrios-Palacios, National Institute of Medical Sciences and Nutrition Salvador Zubirán, Experimental Pathology Section, Ciudad de México, México, E-mail: email@example.com. Ma. Isabel Salazar, Laboratorio de Virología e Inmunovirología, Depto. Microbiología Escuela Nacional de Ciencias Biológicas Instituto Politécnico Nacional, Ciudad de México, México, E-mail: firstname.lastname@example.org. Carlos Machain-Williams, Laboratorio de Arbovirologia, Centro de Investigaciones Regionales “Dr. Hideyo Noguchi,” Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico, E-mail: email@example.com. Jonathan Cisneros-Pano, Laboratorio de Microbiología Médica, Universidad Autonoma de Guerrero, Chilpancingo, Guerrero, México, E-mail: firstname.lastname@example.org. Lauren A. McKeen, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, E-mail: email@example.com.