Urban foci of murine typhus involving cat fleas (Ctenocephalides felis felis) collected from opossums in Mexico City

Abstract

Murine typhus, a neglected rickettsiosis caused by Rickettsia typhi, is a common disease in several Latin-American countries. The sylvatic life cycle of R. typhi encompasses the presence of several wild mammals, particularly opossums of the genus Didelphis and their associated fleas. Due to the colonization of wild environments by human populations, the increase in contact with opossum fleas has generated the presence of urban outbreaks of typhus. For this reason, the aim of our study was to identify the presence and diversity of Rickettsia sp. in fleas collected from opossums of an urban reserve in Mexico City. Opossums were captured from February to September 2017. For the detection of Rickettsia DNA, fragments of 800 bp of the citrate synthase (gltA) and the outer membrane protein B (ompB) were amplified. A total of 141 fleas (111 ♀, 30 ♂) of a single species (Ctenocephalides felis felis) were recovered from 31 Didelphis virginiana. Rickettsia DNA was detected in 17.7% (25/141) of the analysed fleas, recovered from seven infested opossums. The Maximum likelihood of sequences exhibited an identity of 99%-100% with sequences of R. typhi from southern United States. This work represents the first record of R. typhi in fleas from opossums in Mexico.

Murine Typhus in Latin America: Perspectives of a Once Recognized but Now Neglected Vector-Borne Disease

“…ticks from Chiapas state; 97 and recently, in C. felis collected from opossums (D. virginiana) from an urban ecological reserve in Mexico City. 70 These results suggest a mixed ecology of murine typhus in Mexico.…”

“…69 Currently, in the United States and parts of Mexico, an alternate zoonotic cycle exists, apparently involving opossums (Didelphis virginiana) and cat fleas (Ctenocephalides felis) as the amplifying reservoir host and vector, respectively. 70 It is referred to as the suburban cycle of transmission for its link to endemic foci in suburban areas of California, away from areas of denser urban rat populations. 71,72…”

Confirmation of the presence of Rickettsia felis infecting Ornithodoros puertoricensis in Mexico

“…talaje , (Canto‐Osorio et al, 2020; Dzul‐Rosado et al, 2021; Guzmán‐Cornejo et al, 2022). Additionally, Rickettsia typhi has been recorded in C. felis felis (Santoyo‐Colín et al, 2021). In the US, it has been assumed that opossums function as controlling agents of the populations of potential vectors (Hennessy & Hild, 2021).…”

“…The role of marsupials as possible amplifying hosts of several members of the Rickettsia genus has recently been highlighted. In the United States, Brazil, and Mexico, several surveillance studies have been reported that these mammals carry a wide range of ectoparasites infected with various species of Rickettsia , such as Rickettsia rickettsii Brumpt and Rickettsia typhi (Wolbach and Todd) (Blanton et al, 2016; Santoyo‐Colin et al 2021; Serpa et al, 2021). Because marsupials can present massive infestations by other groups of hematophagous arthropods such as the cat flea Ctenocephalides felis felis Siphonaptera: Pulicidae (Bouche), it is possible to suspect that several flea‐borne Rickettsia such as R. typhi and R. felis can be transmitted by cofeeding to other hematophagous arthropods (such as ticks) that feed simultaneously and in close proximity to the infected competent vector (Colunga‐Salas et al, 2022; Fongsaran et al, 2022).…”