#Density-dependence and #persistence of #Morogoro #arenavirus #transmission in a fluctuating population of its reservoir host (J Anim Ecol., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

J Anim Ecol. 2019 Sep 23. doi: 10.1111/1365-2656.13107. [Epub ahead of print]

Density-dependence and persistence of Morogoro arenavirus transmission in a fluctuating population of its reservoir host.

Mariën J1, Borremans B1,2,3, Verhaeren C1, Kirkpatrick L1, Gryseels S1,4,5, Goüy de Bellocq J6, Günther S7, Sabuni CA8, Massawe AW8, Reijniers J1,9, Leirs H1.

Author information: 1 Evolutionary Ecology Group, University of Antwerp, Antwerp, Belgium. 2 Department of Ecology and Evolutionary Biology, University of California, Los Angeles, USA. 3 Interuniversity Institute for Biostatistics and statistical Bioinformatics (I-BIOSTAT), Hasselt University, Hasselt, Belgium. 4 Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, USA. 5 Clinical and Epidemiological Virology, Rega Institute, KU Leuven, Leuven, Belgium. 6 Institute of Vertebrate Biology, Research Facility Studenec, The Czech Academy of Sciences, Brno, Czech Republic. 7 Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany. 8 PestManagement Centre, Sokoine University of Agriculture, Morogoro, Tanzania. 9 Department of Engineering Management, University of Antwerp, Antwerp, Belgium.

 

Abstract

1.A key aim in wildlife disease ecology is to understand how host and parasite characteristics influence parasite transmission and persistence. Variation in host population density can have strong impacts on transmission and outbreaks, and theory predicts particular transmission-density patterns depending on how parasites are transmitted between individuals. Here, we present the results of a study on the dynamics of Morogoro arenavirus in a population of multimammate mice (Mastomys natalensis). This widespread African rodent, which is also the reservoir host of Lassa arenavirus in West Africa, is known for its strong seasonal density fluctuations driven by food availability.

2.We investigated to what degree virus transmission changes with host population density and how the virus might be able to persist during periods of low host density.

3.A seven-year capture-mark-recapture study was conducted in Tanzania where rodents were trapped monthly and screened for the presence of antibodies against Morogoro virus. Observed seasonal seroprevalence patterns were compared with those generated by mathematical transmission models to test different hypotheses regarding the degree of density-dependence and the role of chronically infected individuals.

4.We observed that Morogoro virus seroprevalence correlates positively with host density with a lag of one to four months. Model results suggest that the observed seasonal seroprevalence dynamics can be best explained by a combination of vertical and horizontal transmission, and that a small number of animals needs to be infected chronically to ensure viral persistence.

5.Transmission dynamics and viral persistence were best explained by the existence of both acutely and chronically infected individuals, and by seasonally changing transmission rates. Due to the presence of chronically infected rodents, rodent control is unlikely to be a feasible approach for eliminating arenaviruses such as Lassa virus from Mastomys populations.

© 2019 The Authors. Journal of Animal Ecology © 2019 British Ecological Society.

PMID: 31545505 DOI: 10.1111/1365-2656.13107

Keywords: Arenavirus; Wildlife; Rodents; Morogoro virus; Seroprevalence; Tanzania.

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#Hantavirus host assemblages and #human disease in the #Atlantic #Forest (PLoS Negl Trop Dis., abstract)

[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Hantavirus host assemblages and human disease in the Atlantic Forest

Renata L. Muylaert , Ricardo Siqueira Bovendorp, Gilberto Sabino-Santos Jr, Paula R. Prist, Geruza Leal Melo, Camila de Fátima Priante, David A. Wilkinson, Milton Cezar Ribeiro, David T. S. Hayman

Published: August 12, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007655 / This is an uncorrected proof.

 

Abstract

Several viruses from the genus Orthohantavirus are known to cause lethal disease in humans. Sigmodontinae rodents are the main hosts responsible for hantavirus transmission in the tropical forests, savannas, and wetlands of South America. These rodents can shed different hantaviruses, such as the lethal and emerging Araraquara orthohantavirus. Factors that drive variation in host populations may influence hantavirus transmission dynamics within and between populations. Landscape structure, and particularly areas with a predominance of agricultural land and forest remnants, is expected to influence the proportion of hantavirus rodent hosts in the Atlantic Forest rodent community. Here, we tested this using 283 Atlantic Forest rodent capture records and geographically weighted models that allow us to test if predictors vary spatially. We also assessed the correspondence between proportions of hantavirus hosts in rodent communities and a human vulnerability to hantavirus infection index across the entire Atlantic Forest biome. We found that hantavirus host proportions were more positively influenced by landscape diversity than by a particular habitat or agricultural matrix type. Local small mammal diversity also positively influenced known pathogenic hantavirus host proportions, indicating that a plasticity to habitat quality may be more important for these hosts than competition with native forest dwelling species. We found a consistent positive effect of sugarcane and tree plantation on the proportion of rodent hosts, whereas defaunation intensity did not correlate with the proportion of hosts of potentially pathogenic hantavirus genotypes in the community, indicating that non-defaunated areas can also be hotspots for hantavirus disease outbreaks. The spatial match between host hotspots and human disease vulnerability was 17%, while coldspots matched 20%. Overall, we discovered strong spatial and land use change influences on hantavirus hosts at the landscape level across the Atlantic Forest. Our findings suggest disease surveillance must be reinforced in the southern and southeastern regions of the biome where the highest predicted hantavirus host proportion and levels of vulnerability spatially match. Importantly, our analyses suggest there may be more complex rodent community dynamics and interactions with human disease than currently hypothesized.

 

Author summary

Hantaviruses cause disease in people, mainly following transmission from wild rodents to people through contact with infected excreta. Wild rodents use different habitats, and many survive even in anthropogenically changed environments, but to an unknown extent. The objective of our study was to understand how these rodents respond to habitat change in the landscape, to biodiversity and to climate. We measured the proportion of pathogenic hantavirus hosts in the rodent community. We then investigated the spatial correspondence between this proportion and a vulnerability to pathogenic hantavirus infection index in humans within the Atlantic Forest. We found 12 well represented species of rodents that can carry at least one hantavirus genotype. Despite high variation in the host proportion data, the peaks of human vulnerability to disease occurs at higher levels of habitat diversity in the landscape, intermediate levels of rainfall, and areas with less than 15 species in the local small mammal community. Our results suggest hantavirus surveillance and prevention measures are needed in the south and south-east regions of Brazil where highest host proportions and levels of vulnerability spatially match.

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Citation: Muylaert RL, Bovendorp RS, Sabino-Santos G Jr, Prist PR, Melo GL, Priante CdF, et al. (2019) Hantavirus host assemblages and human disease in the Atlantic Forest. PLoS Negl Trop Dis 13(8): e0007655. https://doi.org/10.1371/journal.pntd.0007655

Editor: Colleen B. Jonsson, University of Tennessee Health Science Center College of Medicine Memphis, UNITED STATES

Received: January 17, 2019; Accepted: July 24, 2019; Published: August 12, 2019

Copyright: © 2019 Muylaert et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: The input data is provided in S2 Table. All relevant data are within the manuscript, its Supporting Information files and in the ATLANTIC series files. The data underlying the results presented in the study is available at: https://github.com/LEEClab/Atlantic_series/tree/master/ATLANTIC_SMALL_MAMMALS. Atlantic Forest data is available at: https://github.com/LEEClab/ATLANTIC-limits.

Funding: This work was supported by Fundação de Amparo à Pesquisa do Estado de São Paulo FAPESP to RLM (https://bv.fapesp.br/pt/pesquisador/176171/renata-de-lara-muylaert/) (2015/17739-4, 2017/21816-0), GSSJ (https://bv.fapesp.br/pt/pesquisador/79234/gilberto-sabino-dos-santos-junior/) (2017/21816-0), RSB (https://bv.fapesp.br/pt/pesquisador/76113/ricardo-siqueira-bovendorp/) (2013/25441-0), PRP (2017/11666-0), and MCR (https://bv.fapesp.br/pt/pesquisador/176172/milton-cezar-ribeiro/) (2013/50421-2); Royal Society Te Apārangi Rutherford Discovery Fellowship to DTSH (https://royalsociety.org.nz/what-we-do/funds-and-opportunities/rutherford-discovery-fellowships/rutherford-discovery-fellowship-recipients/david-hayman/) (RDF-MAU1701); Conselho Nacional de Desenvolvimento Científico e Tecnológico CNPQ to MCR (425746/2016-0); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CAPES to MCR (312045/2013-1; 312292/2016-3) and RLM (33004137); and New Zealand Food Safety Science and Research Centre (https://www.nzfssrc.org.nz/) to DW (2019). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing interests: The authors have declared that no competing interests exist.

Keywords: Orthohantavirus; Hantavirus; Rodents; Human; Brazil.

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Field #assessment of #insecticide #dusting and #bait station #treatment impact against #rodent #flea and house flea species in the #Madagascar #plague context (PLoS Negl Trop Dis., abstract)

[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]

OPEN ACCESS /  PEER-REVIEWED / RESEARCH ARTICLE

Field assessment of insecticide dusting and bait station treatment impact against rodent flea and house flea species in the Madagascar plague context

Adélaïde Miarinjara  , Soanandrasana Rahelinirina , Nadia Lova Razafimahatratra, Romain Girod, Minoarisoa Rajerison , Sebastien Boyer

Published: August 6, 2019 / DOI: https://doi.org/10.1371/journal.pntd.0007604 / This is an uncorrected proof.

 

Abstract

Bubonic is the most prevalent plague form in Madagascar. Indoor ground application of insecticide dust is the conventional method used to control potentially infected rodent fleas that transmit the plague bacterium from rodents to humans. The use of bait stations is an alternative approach for vector control during plague epidemics, as well as a preventive control method during non-epidemic seasons. Bait stations have many advantages, principally by reducing the amount of insecticide used, lowering the cost of the treatment and minimizing insecticide exposure in the environment. A previous study reported promising results on controlling simultaneously the reservoir and vectors, when slow-acting rodenticide was incorporated in bait stations called “Boîtes de Kartman”. However, little evidence of an effective control of the fleas prior to the elimination of rodents was found. In this study, we evaluated bait stations containing insecticide powder and non-toxic attractive rodent bait for their potential to control rat fleas. Its efficacy was compared to the standard method. The impact of both methods on indoor and outdoor rodent fleas, as well as the human household flea Pulex irritans were analyzed at different time points after treatments. Bait stations did not cause any significant immediate or delayed reduction of rat fleas and increasing the number of operational bait stations per household did not significantly improve their efficacy. Insecticide ground dusting appeared to be the most efficient method to control indoor rat fleas. Both methods appeared to have little impact on the density of outdoor rat fleas and human fleas. These results demonstrate limited effectiveness for bait stations and encourage the maintenance of insecticide dusting as a first-line control strategy in case of epidemic emergence of plague, when immediate effect on rodent fleas is needed. Recommendations are given to improve the efficacy of the bait station method.

 

Author summary

Insecticide ground dusting inside houses is the recommended measure to control rat fleas responsible for bubonic plague transmission. The main inconvenience of this method is the direct contact of houseowners to the toxic insecticide dust and spillage in environment. A bait station approach, where the insecticide is confined in a box or tunnel containing rodent attractant, seems to be a valuable complementary or alternative vector control tool. However currently, little is known about its real efficacy on reducing or eliminating fleas harbored by rats. Guidelines regarding its implementation (density and duration of use) as vector control tool are lacking. Those questions were addressed during a field trial study, where bait stations were deployed at different densities per household and followed up at different time points. The efficacy of bait station was compared to the standard method. The present study allowed to demonstrate that bait station approach requires more improvements to be efficient. Meanwhile, insecticide ground dusting is still recommended for to control rat fleas during epidemics.

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Citation: Miarinjara A, Rahelinirina S, Razafimahatratra NL, Girod R, Rajerison M, Boyer S (2019) Field assessment of insecticide dusting and bait station treatment impact against rodent flea and house flea species in the Madagascar plague context. PLoS Negl Trop Dis 13(8): e0007604. https://doi.org/10.1371/journal.pntd.0007604

Editor: José Reck Jr., Instituto de Pesquisas Veterinarias Desiderio Finamor, BRAZIL

Received: February 5, 2019; Accepted: July 4, 2019; Published: August 6, 2019

Copyright: © 2019 Miarinjara et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Data Availability: All relevant data are within the manuscript and its Supporting Information files.

Funding: This work was supported and funded by Institut Pasteur de Madagascar. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Competing interests: The authors have declared that no competing interests exist.

Keywords: Plague; Bubonic plague; Fleas; Rodents; Insecticides; Madagascar.

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An Evaluation of Removal Trapping to Control #Rodents Inside Homes in a #Plague-Endemic Region of Rural Northwestern #Uganda (Vector Borne Zoonotic Dis., abstract)

[Source: Vector Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

An Evaluation of Removal Trapping to Control Rodents Inside Homes in a Plague-Endemic Region of Rural Northwestern Uganda

Eisen Rebecca J., Atiku Linda A., Boegler Karen A., Mpanga Joseph T., Enscore Russell E., MacMillan Katherine, and Gage Kenneth L.

Published Online: 16 May 2018 / DOI: https://doi.org/10.1089/vbz.2018.2276

 

Abstract

Rodents pose a significant threat to human health, particularly in rural subsistence farming communities in Africa, where rodents threaten food security and serve as reservoirs of human pathogens, including the agents of plague, leptospirosis, murine typhus, rat-bite fever, Lassa fever, salmonellosis, and campylobacteriosis. Our study focused on the plague-endemic West Nile region of Uganda, where a majority of residents live in Uganda government-defined poverty, rely on subsistence farming for a living, and frequently experience incursions of rodents into their homes. In this study, we show that rodent removal was achieved in a median of 6 days of intensive lethal trapping with multiple trap types (range: 0–16 days). However, rodent abundance in 68.9% of homesteads returned to pretreatment levels within a median of 8 weeks (range 1–24 weeks), and at least a single rodent was captured in all homesteads by a median of 2 weeks (range 1–16 weeks) after removal efforts were terminated. Results were similar between homesteads that practiced rodent control whether or not their neighbors implemented similar strategies. Overall, intensive lethal trapping inside homes appears to be effective at reducing rodent abundance, but control was short lived after trapping ceased.

Keywords: Plague; Yersinia Pestis; Rodents; Uganda.

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#Movement #Patterns of Small #Rodents in #Lassa Fever-Endemic Villages in #Guinea (Ecohealth, abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

Ecohealth. 2018 Mar 23. doi: 10.1007/s10393-018-1331-8. [Epub ahead of print]

Movement Patterns of Small Rodents in Lassa Fever-Endemic Villages in Guinea.

Mariën J1, Kourouma F2, Magassouba N2, Leirs H3, Fichet-Calvet E4.

Author information: 1 Evolutionary Ecology Group, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium. joachim.marien@uantwerpen.be. 2 Laboratoire des Fièvres Hémorragiques, Nongo, Conakry, Guinea. 3 Evolutionary Ecology Group, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium. 4 Bernhard-Nocht-Institute for Tropical Medicine, Hamburg, Germany.

 

Abstract

The Natal multimammate mouse (Mastomys natalensis) is the reservoir host of Lassa arenavirus, the etiological agent of Lassa fever in humans. Because there exists no vaccine for human use, rodent control and adjusting human behavior are currently considered to be the only options for Lassa fever control. In order to develop efficient rodent control programs, more information about the host’s ecology is needed. In this study, we investigated the spatial behavior of M. natalensis and other small rodents in two capture-mark-recapture and four dyed bait (Rhodamine B) experiments in Lassa fever-endemic villages in Upper Guinea. During the capture-mark-recapture studies, 23% of the recaptured M. natalensis moved between the houses and proximate fields. While M. natalensis was found over the entire study grid (2 ha), other rodent species (Praomys daltoni, Praomys rostratus, Lemniscomys striatus, Mus spp.) were mostly trapped in the surrounding fields. Distances between recapture occasions never exceeded 100 m for all rodent species. During the dyed bait experiments, 11% of M. natalensis and 41% of P. daltoni moved from the fields to houses. We conclude that commensal M. natalensis easily moves between houses and proximate fields in Guinea. We therefore consider occasional domestic rodent elimination to be an unsustainable approach to reduce Lassa virus transmission risk to humans, as M. natalensis is likely to reinvade houses quickly from fields in which rodents are not controlled. A combination of permanent rodent elimination with other control strategies (e.g., make houses rodent proof or attract predators) could be more effective for Lassa fever control, but must be further investigated.

KEYWORDS: Capture-mark-recapture; Lassa virus; Mastomys natalensis; Rhodamine B; Rodent control

PMID: 29572697 DOI: 10.1007/s10393-018-1331-8

Keywords: Lassa Fever; Rodents; Guinea.

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#Serological #Survey of #Zoonotic #Viruses in Invasive and Native Commensal #Rodents in #Senegal, West Africa (Vector Borne Zoo Dis., abstract)

[Source: Vector-Borne and Zoonotic Diseases, full page: (LINK). Abstract, edited.]

Vector-Borne and Zoonotic Diseases

Serological Survey of Zoonotic Viruses in Invasive and Native Commensal Rodents in Senegal, West Africa

To cite this article: Diagne Christophe A., Charbonnel Nathalie, Henttonen Heikki, Sironen Tarja, and Brouat Carine. Vector-Borne and Zoonotic Diseases. September 2017, ahead of print. https://doi.org/10.1089/vbz.2017.2135

Online Ahead of Print: September 5, 2017

Author information: Christophe A. Diagne,1,2,3 Nathalie Charbonnel,4 Heikki Henttonen,5 Tarja Sironen,6 and Carine Brouat1

1 CBGP, IRD, CIRAD, INRA, Montpellier SupAgro, University of Montpellier, Montpellier, France. 2 BIOPASS (IRD-CBGP, ISRA, UCAD), Dakar, Senegal. 3 Département de Biologie Animale, Faculté des Sciences et Techniques, Université Cheikh Anta Diop (UCAD), Dakar, Senegal. 4 CBGP, INRA, CIRAD, IRD, Montpellier SupAgro, University of Montpellier, Montpellier, France. 5 Forest and Animal Ecology, Natural Resources Institute Finland, Helsinki, Finland. 6 Department of Virology, University of Helsinki, Helsinki, Finland.

Address correspondence to: Christophe Diagne, Centre de Biologie pour la Gestion des Populations (CBGP)755 avenue du Campus Agropolis, Campus de Baillarguet CS 30016, 34988 Montferrier/Lez cedex, France, E-mail: chrisdiagne89@hotmail.fr

 

ABSTRACT

Increasing studies on rodent-borne diseases still highlight the major role of rodents as reservoirs of numerous zoonoses of which the frequency is likely to increase worldwide as a result of accelerated anthropogenic changes, including biological invasions. Such a situation makes pathogen detection in rodent populations important, especially in the context of developing countries characterized by high infectious disease burden. Here, we used indirect fluorescent antibody tests to describe the circulation of potentially zoonotic viruses in both invasive (Mus musculus domesticus and Rattus rattus) and native (Mastomys erythroleucus and Mastomys natalensis) murine rodent populations in Senegal (West Africa). Of the 672 rodents tested, we reported 22 seropositive tests for Hantavirus, Orthopoxvirus, and Mammarenavirus genera, and no evidence of viral coinfection. This study is the first to report serological detection of Orthopoxvirus in rodents from Senegal, Mammarenavirus in R. rattus from Africa, and Hantavirus in M. m. domesticus and in M. erythroleucus. Further specific identification of the viral agents highlighted here is urgently needed for crucial public health concerns.

Keywords: Serosurveys; Rodents; Senegal; Orthopoxvirus; Mammarenavirus; Hantavirus.

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#Prevalence of #Lassa virus among #rodents trapped in three South-South States of #Nigeria (J Vector Borne Dis., abstract)

[Source: US National Library of Medicine, full page: (LINK). Abstract, edited.]

J Vector Borne Dis. 2017 Apr-Jun;54(2):146-150.

Prevalence of Lassa virus among rodents trapped in three South-South States of Nigeria.

Agbonlahor DE1, Erah A2, Agba IM3, Oviasogie FE4, Ehiaghe AF5, Wankasi M6, Eremwanarue OA7, Ehiaghe IJ7, Ogbu EC7, Iyen RI7, Abbey S6, Tatfeng MY6, Uhunmwangho J4.

Author information: 1 Lahor Research Laboratories and Medical Centre, Benin City, Edo State; Department of Medical Laboratory Science, College of Health Sciences, Niger Delta University, Amassoma, Bayelsa State, Nigeria. 2 Department of Medical Laboratory Science, Igbinedion University, Okada, Nigeria. 3 Department of Microbiology, Faculty of Life Sciences, University of Benin, Benin City, Nigeria. 4 Department of Medical Laboratory Science, Ambrose Alli University, Ekpoma, Edo State, Nigeria. 5 Lahor Research Laboratories and Medical Centre, Benin City, Edo State; Department of Medical Laboratory Science, Igbinedion University, Okada, Nigeria. 6 Department of Medical Laboratory Science, College of Health Sciences, Niger Delta University, Amassoma, Bayelsa State, Nigeria. 7 Lahor Research Laboratories and Medical Centre, Benin City, Edo State, Nigeria.

 

Abstract

BACKGROUND & OBJECTIVES:

Lassa fever has been endemic in Nigeria since 1969. The rodent Mastomys natalensis has been widely claimed to be the reservoir host of the Lassa virus. This study was designed to investigate the dis- tribution of species of rodents in three states (Edo, Delta and Bayelsa) of Nigeria and to determine the prevalence of Lassa virus amongst trapped rodents in the selected states.

METHODS:

Rodents were trapped during November 2015 to October 2016 from the three states in South-South re- gion of Nigeria. Total RNA was extracted from the blood collected from the trapped rodents. Reverse transcription polymerase chain reaction (RT-PCR) was used to confirm the presence of Lassa virus in the rodents.

RESULTS:

The results revealed that six species of rodents were predominantly present in these geographical locations. Mus musculus (39.4%) had the highest prevalence, closely followed by Rattus rattus (36.1%), R. fuscipus (20.3%), M. natalensis (2%), Myosoricinae soricidae (1.2%) and R. norvegicus (1%). The overall positivity (carrier rate) of Lassa virus was 1.6% amongst the 1500 rodents caught in the three states. In Edo and Delta States, the RT-PCR results showed presence of Lassa virus in R. rattus, M. musculus and M. natalensis. On the other hand, only M. na- talensis was detected with the virus, amongst the species of rodents caught in Bayelsa State. M. natalensis recorded the highest Lassa virus among rodents trapped in Edo (87%), Delta (50%) and Bayelsa (11%) States respectively.

INTERPRETATION & CONCLUSION:

The rather low Lassa virus positive among rodents in Bayelsa State of Nigeria may explain the absence of reports of outbreak of Lassa fever over the past 48 yr in the state. The results also confirmed that apart from Mastomys natalensis, other rodents such as Rattus rattus and Mus musculus may also serve as res- ervoirs for Lassa virus. From the findings of this cross-sectional study, it was concluded that a more comprehensive study on rodents as reservoir host, need to be undertaken across the entire states of Nigeria, for better understanding of the epidemiology and endemicity of Lassa fever.

PMID: 28748835

Keywords: Lassa Fever; Viral Hemorrhagic Fever; Nigeria; Rodents.

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