Geographic Distribution of Hantaviruses Associated with Neotomine and Sigmodontine Rodents, Mexico

Mary L. Milazzo¹, Maria N.B. Cajimat¹, Hannah E. Romo, Jose G. Estrada-Franco, L. Ignacio Iñiguez-Dávalos, Robert D. Bradley, and Charles F. Fulhorst

Author affiliations: University of Texas Medical Branch, Galveston, Texas, USA (M.L. Milazzo, M.N.B. Cajimat, H.E. Romo, J.G. Estrada-Franco, C.F. Fulhorst); Universidad de Guadalajara, Autlán de Navarro, Mexico (L.I. Iñiguez-Dávalos); Texas Tech University, Lubbock, Texas, USA (R.D. Bradley)

Abstract

To increase our knowledge of the geographic distribution of hantaviruses associated with neotomine or sigmodontine rodents in Mexico, we tested 876 cricetid rodents captured in 18 Mexican states (representing at least 44 species in the subfamily Neotominae and 10 species in the subfamily Sigmodontinae) for anti-hantavirus IgG. We found antibodies against hantavirus in 35 (4.0%) rodents. Nucleotide sequence data from 5 antibody-positive rodents indicated that Sin Nombre virus (the major cause of hantavirus pulmonary syndrome [HPS] in the United States) is enzootic in the Mexican states of Nuevo León, San Luis Potosí, Tamaulipas, and Veracruz. However, HPS has not been reported from these states, which suggests that in northeastern Mexico, HPS has been confused with other rapidly progressive, life-threatening respiratory diseases. Analyses of nucleotide sequence data from 19 other antibody-positive rodents indicated that El Moro Canyon virus and Limestone Canyon virus are geographically widely distributed in Mexico.

Hantavirus pulmonary syndrome (HPS) is a potentially fatal zoonosis caused by hantaviruses (family Bunyaviridae, genus Hantavirus) that are principally associated with members of the rodent family Cricetidae, more specifically, members of the subfamily Neotominae or Sigmodontinae (1,2). The viruses known to cause HPS on the North American continent are Bayou virus, Black Creek Canal virus (BCCV), Choclo virus (CHOV), New York virus, and Sin Nombre virus (SNV) (3–7). Other hantaviruses that are principally associated with neotomine or North American sigmodontine rodents include Carrizal virus (CARV), Catacamas virus, El Moro Canyon virus (ELMCV), Huitzilac virus (HUIV), Limestone Canyon virus (LSCV), Montano virus (MTNV), Muleshoe virus (MULV), Playa de Oro virus, and Rio Segundo virus (RIOSV) (8–14).
Specific rodents (usually 1 or 2 closely related species) are the principal hosts of the hantaviruses, for which natural host relationships have been well characterized. The current principal host relationships of some hantaviruses seem to represent a long-term association between viruses in the genus Hantavirus and rodents in the family Cricetidae. Evidence for this ancient relationship includes the association of phylogenetically closely related hantavirus species with phylogenetically closely related allopatric rodent species. For example, Catacamas virus is associated with Coues’s rice rat (Oryzomys couesi) in Honduras, and Bayou virus is associated with the marsh rice rat (Oryzomys palustris) in the southeastern United States (9,15).
The rodent fauna of Mexico comprises the brush mouse (Peromyscus boylii), the deer mouse (P. maniculatus), the western harvest mouse (Reithrodontomys megalotis), the hispid cotton rat (Sigmodon hispidus), the fulvous pygmy rice rat (Oligoryzomys fulvescens), and 122 other species in the Neotominae or Sigmodontinae (16). In the southwestern United States, LSCV, SNV, ELMCV, and MULV are principally associated with rodents of the species P. boylii, P. maniculatus, R. megalotis, and S. hispidus, respectively (10–12,17), and that in Panama, CHOV is principally associated with O. fulvescens (18). Hypothetically, LSCV, SNV, ELMCV, and/or MULV—in association with deer mice (Peromyscus spp.), harvest mice (Reithrodontomys spp.), or cotton rats (Sigmodon spp.)—are widely distributed in northern Mexico, and the hantavirus assemblage of southern Mexico includes CHOV or hantaviruses that are phylogenetically closely related to CHOV.
Our knowledge of the rodent-associated hantaviruses in Mexico includes the following findings: HUIV RNA in a western harvest mouse (R. megalotis) captured in Morelos (8); CARV RNA in a Sumichrast’s harvest mouse (R. sumichrasti) and MTNV RNA in an Orizaba deer mouse (P. beatae) from Guerrero (8); Playa de Oro virus RNA in a Mexican oryzomys (Oryzomys mexicanus) and Jaliscan cotton rat (S. mascotensis) from Colima (13); ELMCV RNA and SNV RNA in western harvest mice from Zacatecas (14); antibody against hantavirus in nimble-footed mice (P. levipes) captured in Tamaulipas (19); and antibody against hantavirus in a North American deer mouse (P. maniculatus), transvolcanic mice (P. hylocetes), black-eared mice (P. melanotis), and Sumichrast’s harvest mouse captured in the state of Mexico (20,21). The purpose of this study was to extend our knowledge of the geographic distribution of hantaviruses associated with neotomine or sigmodontine rodents in Mexico.