Lassa fever in Guinea: II. Distribution and prevalence of Lassa virus infection in small mammals.

Rodents of the genus Mastomys form the reservoir for Lassa virus (LV), an arenavirus that causes a potentially severe hemorrhagic illness, Lassa fever (LF). Although Mastomys rodents exist throughout sub-Saharan Africa, areas of human LF appear to be quite focal. The distribution of small mammals and LV-infected Mastomys has been assessed in only a few countries. We conducted a survey of small mammals in selected regions of Guinea to assess the degree to which LV poses a public health risk in that country. A total of 1,616 small mammals, including 956 (59%) Mastomys, were captured from 444 households and seven bush sites. Mastomys made up > 90% of the captured animals in the savannah, savannah-forest transition, and forest regions of Guinea, while Mus musculus dominated in coastal and urban sites. Animals were analyzed via enzyme-linked immunosorbent assay (ELISA) for LV-specific antigen (blood and spleen homogenate) and IgG antibody (blood only). Virus isolation from spleen homogenates was also performed on a subset of animals. Lassa antibody and antigen were found in 96 (11%) and 46 (5%), respectively, of 884 tested Mastomys. Antibody and antigen were essentially mutually exclusive and showed profiles consistent with vertical transmission of both LV and antibody. LV was isolated only from Mastomys. ELISA antigen constituted an acceptable surrogate for virus isolation, with a sensitivity and specificity when performed on blood of 78% (95% confidence interval: 68-83%) and 98% (95-99%), respectively. The proportion of LV-infected Mastomys per region ranged from 0 to 9% and was highest in the savannah and forest zones. The proportion of infected animals per village varied considerably, even between villages in close proximity. Infected animals tended to cluster in relatively few houses, suggesting the existence of focal "hot spots" of LV-infected Mastomys that may account for the observed heterogeneous distribution of LF.

[1]  T. Yates,et al.  Mammalian reservoirs of arenaviruses. , 2002, Current topics in microbiology and immunology.

[2]  Rosamund F. Lewis,et al.  Short communication: Lassa fever in Sierra Leone: UN peacekeepers are at risk , 2001, Tropical medicine & international health : TM & IH.

[3]  T. Ksiazek,et al.  Lassa fever in Guinea: I. Epidemiology of human disease and clinical observations. , 2001, Vector borne and zoonotic diseases.

[4]  T. Hawn,et al.  Emerging Infectious Diseases , 2011, Berkowitz’s Pediatrics: A Primary Care Approach.

[5]  Stuart T. Nichol,et al.  Genetic Diversity among Lassa Virus Strains , 2000, Journal of Virology.

[6]  T. Ksiazek,et al.  Diagnosis and Clinical Virology of Lassa Fever as Evaluated by Enzyme-Linked Immunosorbent Assay, Indirect Fluorescent-Antibody Test, and Virus Isolation , 2000, Journal of Clinical Microbiology.

[7]  J. Meulen,et al.  Detection of Lassa Virus Antinucleoprotein Immunoglobulin G (IgG) and IgM Antibodies by a Simple Recombinant Immunoblot Assay for Field Use , 1998, Journal of Clinical Microbiology.

[8]  H. Leirs,et al.  SPATIAL DYNAMICS OF MASTOMYS NATALENSIS IN A FIELD-FALLOW MOSAIC IN TANZANIA. , 1997 .

[9]  J. Childs,et al.  Patterns of association with host and habitat: antibody reactive with Sin Nombre virus in small mammals in the major biotic communities of the southwestern United States. , 1997, The American journal of tropical medicine and hygiene.

[10]  J. Chang-Claude,et al.  Hunting of peridomestic rodents and consumption of their meat as possible risk factors for rodent-to-human transmission of Lassa virus in the Republic of Guinea. , 1996, The American journal of tropical medicine and hygiene.

[11]  J. Childs,et al.  Methods for trapping and sampling small mammals for virologic testing , 1995 .

[12]  I. Lukashevich,et al.  Lassa virus activity in Guinea: Distribution of human antiviral antibody defined using enzyme‐linked immunosorbent assay with recombinant antigen , 1993, Journal of medical virology.

[13]  J. Childs,et al.  A longitudinal study of Junin virus activity in the rodent reservoir of Argentine hemorrhagic fever. , 1992, The American journal of tropical medicine and hygiene.

[14]  J. Frame.  Clinical features of Lassa fever in Liberia. , 1989, Reviews of infectious diseases.

[15]  C. B. Robbins,et al.  Comments on the systematics of Mastomys Thomas 1915 with the description of a new West African species (Mammalia: Rodentia: Muridae) , 1989 .

[16]  J. McCormick,et al.  Viral hemorrhagic fever antibodies in Nigerian populations. , 1988, The American journal of tropical medicine and hygiene.

[17]  J. McCormick,et al.  A case-control study of the clinical diagnosis and course of Lassa fever. , 1987, The Journal of infectious diseases.

[18]  E. S. Smith,et al.  A prospective study of the epidemiology and ecology of Lassa fever. , 1987, The Journal of infectious diseases.

[19]  J. McCormick.  Epidemiology and control of Lassa fever. , 1987, Current topics in microbiology and immunology.

[20]  A. Shepherd,et al.  IDENTIFICATION OF IPPY AS A LASSA-FEVER-RELATED VIRUS , 1985, The Lancet.

[21]  J. McCormick,et al.  Antibodies to Lassa and Lassa-like viruses in man and mammals in the Central African Republic. , 1985, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[22]  P. Jahrling,et al.  Detection of Lassa virus antigens and Lassa virus-specific immunoglobulins G and M by enzyme-linked immunosorbent assay , 1984, Journal of clinical microbiology.

[23]  P. Jahrling,et al.  Endemic Lassa fever in Liberia. II. Serological and virological findings in hospital patients. , 1984, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[24]  P. Jahrling,et al.  Endemic Lassa fever in Liberia. I. Clinical and epidemiological aspects at Curran Lutheran Hospital, Zorzor, Liberia. , 1984, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[25]  J. McCormick,et al.  Case-control study of Mastomys natalensis and humans in Lassa virus-infected households in Sierra Leone. , 1983, The American journal of tropical medicine and hygiene.

[26]  F. Petter,et al.  Different species in genus Mastomys from Western, Central and Southern Africa (Rodentia, Muridae) , 1983 .

[27]  J. McCormick,et al.  An arenavirus isolated from wild-caught rodents (Pramys species) in the Central African Republic. , 1983, Intervirology.

[28]  O. Tomori,et al.  Recovery of a Lassa-related arenavirus in Zimbabwe. , 1981, The American journal of tropical medicine and hygiene.

[29]  M. Buchmeier,et al.  The virology and immunobiology of lymphocytic choriomeningitis virus infection. , 1980, Advances in immunology.

[30]  F. Murphy,et al.  CHAPTER 10 – Arenaviruses: Persistent Infection and Viral Survival in Reservoir Hosts , 1978 .

[31]  K. Johnson,et al.  Isolation of an arenavirus closely related to Lassa virus from Mastomys natalensis in south-east Africa. , 1977, Bulletin of the World Health Organization.

[32]  M. Isaäcson.  The ecology of Praomys (Mastomys) natalensis in southern Africa. , 1975, Bulletin of the World Health Organization.

[33]  T. Monath,et al.  Lassa virus infection in Mastomys natalensis in Sierra Leone. Gross and microscopic findings in infected and uninfected animals. , 1975, Bulletin of the World Health Organization.

[34]  O. Tomori,et al.  Lassa fever in Onitsha, East Central State, Nigeria in 1974. , 1975, Bulletin of the World Health Organization.

[35]  J. Frame.  Surveillance of Lassa fever in missionaries stationed in West Africa. , 1975, Bulletin of the World Health Organization.

[36]  T. Monath,et al.  Recent isolations of Lassa virus from Nigerian rodents. , 1975, Bulletin of the World Health Organization.

[37]  T. Monath,et al.  Lassa fever in the Eastern Province of Sierra Leone, 1970-1972. I. Epidemiologic studies. , 1974, The American journal of tropical medicine and hygiene.

[38]  T. Monath,et al.  Lassa Virus Isolation from Mastomys natalensis Rodents during an Epidemic in Sierra Leone , 1974, Science.

[39]  T. Monath,et al.  Clinical presentation of Lassa fever cases during the hospital epidemic at Zorzor, Liberia, March-April 1972. , 1973, The American journal of tropical medicine and hygiene.

[40]  B. Henderson,et al.  Lassa fever. Virological and serological studies. , 1972, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[41]  B. Henderson,et al.  Lassa fever. Epidemiological aspects of the 1970 epidemic, Jos, Nigeria. , 1972, Transactions of the Royal Society of Tropical Medicine and Hygiene.

[42]  J. Frame,et al.  Lassa fever, a new virus disease of man from West Africa. I. Clinical description and pathological findings. , 1970, The American journal of tropical medicine and hygiene.

[43]  J. Casals,et al.  Lassa fever, a new virus disease of man from West Africa. 3. Isolation and characterization of the virus. , 1970, The American journal of tropical medicine and hygiene.

[44]  D. R. Rosevear.  The rodents of West Africa , 1969 .

[45]  R. T. Hatt.  The mammals of the Atlantica Ecological Research Station, Southern Rhodesia , 1963, Zoologica : scientific contributions of the New York Zoological Society..