Tracking of Mammals and Their Fleas for Plague Surveillance in Madagascar, 2018–2019

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  • 1 Plague Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar;
  • | 2 Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar;
  • | 3 Central Laboratory for Plague, Ministry of Public Health, Antananarivo, Madagascar;
  • | 4 National Plague Control Program, Ministry of Public Health, Antananarivo, Madagascar;
  • | 5 U.S. President’s Malaria Initiative, Centers for Disease Control and Prevention, Antananarivo, Madagascar;
  • | 6 U.S. President’s Malaria Initiative, Centers for Disease Control and Prevention, Atlanta, Georgia

Plague, a zoonotic disease caused by the bacterium Yersinia pestis, remains a major public health threat in Madagascar. To better understand the risk of transmission to humans and to guide targeted plague prevention and control measures, a survey of Y. pestis infection and exposure in mammals and their fleas was implemented. Small mammals were captured in five districts of Madagascar ranging in levels of plague endemicity, as measured by notified cases, from none to active foci. Blood and spleen samples and fleas were collected from small mammals for the detection of anti–Y. pestis F1 antibodies by ELISA, F1 antigens by rapid diagnostic tests, and pla, caf1, and inv genes by polymerase chain reaction. Some rodent fleas were kept alive and reared in the insectary to assess susceptibility to insecticides. Blood was also collected from 15 dogs and tested for anti-F1 antibodies. A total of 557 spleens, 484 sera, and 1,539 fleas were collected from 557 rodents and shrews. Nineteen (3.4%) spleens were positive for F1 antigen, most from Toamasina (N = 13), a historical plague focus. One dog was also found seropositive in Toamasina. Twenty-two (4.5%) serologic specimens from small mammals were positive for anti-F1 antibodies. The flea index was highest in the city of Antananarivo (8.8). No flea was positive for Y. pestis DNA. Flea populations exhibited resistance to various insecticides weakening the efficacy of vector control. This study highlights the potential use of animal-based surveillance to identify the risk of plague transmission in endemic and nonendemic foci for targeted prevention and control.

Author Notes

Address correspondence to Soanandrasana Rahelinirina, Institut Pasteur de Madagascar, P.O. Box 1274, Ambatofotsikely, Antananarivo 101, Madagascar. E-mail: rahelinirina@pasteur.mg

These authors contributed equally to this work.

These authors contributed equally to this work.

Financial support: This work was supported by USAID through the Surveillance and Data for Management project (Grant No. AID-687-G-13-00003). SZ and CD were supported by funding from the U.S. President’s Malaria Initiative.

Disclosure: The findings and conclusions in this manuscript are those of the author(s) and do not necessarily represent the official position of the Centers for Disease Control and Prevention or the U.S. President’s Malaria Initiative.

Authors’ addresses: Mireille Harimalala, Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar, E-mail: hmireille@pasteur.mg. Jerry Silvio Rakotoniaina, Central Laboratory for Plague, Ministry of Public Health, Antananarivo, Madagascar, E-mail: docjerrysilvio@yahoo.com. Mamy Gabriel Randriamanantsoa, National Plague Control Program, Ministry of Public Health, Antananarivo, Madagascar, E-mail: gabrielmamydr@yahoo.fr. Catherine Dentinger and Sarah Zohdy, U.S. President’s Malaria Initiative, Centers for Disease Control and Prevention, Antananarivo, Madagascar, E-mails: cgd1@cdc.gov and ykr2@cdc.gov. Romain Girod, Medical Entomology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar, E-mail: rgirod@pasteur.mg. Minoarisoa Rajerison, Plague Unit, WHO Collaborating Center, Institut Pasteur de Madagascar, Antananarivo, Madagascar, E-mail: mino@pasteur.mg.

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