High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study.
BACKGROUND: The Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus. RVFV mostly causes outbreaks among domestic ruminants with a major economic impact. Human infections are associated with these events, with a fatality rate of 0.5-2%. Since the virus is able to use many mosquito specie...
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ftdoajarticles:oai:doaj.org/article:ef790eece9d04a34b2c8da87db36bead 2023-05-15T15:15:35+02:00 High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. Norbert Heinrich Elmar Saathoff Nina Weller Petra Clowes Inge Kroidl Elias Ntinginya Harun Machibya Leonard Maboko Thomas Löscher Gerhard Dobler Michael Hoelscher 2012-01-01T00:00:00Z https://doi.org/10.1371/journal.pntd.0001557 https://doaj.org/article/ef790eece9d04a34b2c8da87db36bead EN eng Public Library of Science (PLoS) http://europepmc.org/articles/PMC3313937?pdf=render https://doaj.org/toc/1935-2735 1935-2735 doi:10.1371/journal.pntd.0001557 https://doaj.org/article/ef790eece9d04a34b2c8da87db36bead PLoS Neglected Tropical Diseases, Vol 6, Iss 3, p e1557 (2012) Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 article 2012 ftdoajarticles https://doi.org/10.1371/journal.pntd.0001557 2022-12-31T13:20:01Z BACKGROUND: The Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus. RVFV mostly causes outbreaks among domestic ruminants with a major economic impact. Human infections are associated with these events, with a fatality rate of 0.5-2%. Since the virus is able to use many mosquito species of temperate climates as vectors, it has a high potential to spread to outside Africa. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a stratified, cross-sectional sero-prevalence survey in 1228 participants from Mbeya region, southwestern Tanzania. Samples were selected from 17,872 persons who took part in a cohort study in 2007 and 2008. RVFV IgG status was determined by indirect immunofluorescence. Possible risk factors were analyzed using uni- and multi-variable Poisson regression models. We found a unique local maximum of RVFV IgG prevalence of 29.3% in a study site close to Lake Malawi (N = 150). The overall seroprevalence was 5.2%. Seropositivity was significantly associated with higher age, lower socio-economic status, ownership of cattle and decreased with distance to Lake Malawi. A high vegetation density, higher minimum and lower maximum temperatures were found to be associated with RVFV IgG positivity. Altitude of residence, especially on a small scale in the high-prevalence area was strongly correlated (PR 0.87 per meter, 95% CI = 0.80-0.94). Abundant surface water collections are present in the lower areas of the high-prevalence site. RVF has not been diagnosed clinically, nor an outbreak detected in the high-prevalence area. CONCLUSIONS: RVFV is probably circulating endemically in the region. The presence of cattle, dense vegetation and temperate conditions favour mosquito propagation and virus replication in the vector and seem to play major roles in virus transmission and circulation. The environmental risk-factors that we identified could serve to more exactly determine areas at risk for RVFV endemicity. Article in Journal/Newspaper Arctic Directory of Open Access Journals: DOAJ Articles Arctic PLoS Neglected Tropical Diseases 6 3 e1557 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
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ftdoajarticles |
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English |
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Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 |
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Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 Norbert Heinrich Elmar Saathoff Nina Weller Petra Clowes Inge Kroidl Elias Ntinginya Harun Machibya Leonard Maboko Thomas Löscher Gerhard Dobler Michael Hoelscher High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. |
topic_facet |
Arctic medicine. Tropical medicine RC955-962 Public aspects of medicine RA1-1270 |
description |
BACKGROUND: The Rift Valley fever virus (RVFV) is an arthropod-borne phlebovirus. RVFV mostly causes outbreaks among domestic ruminants with a major economic impact. Human infections are associated with these events, with a fatality rate of 0.5-2%. Since the virus is able to use many mosquito species of temperate climates as vectors, it has a high potential to spread to outside Africa. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a stratified, cross-sectional sero-prevalence survey in 1228 participants from Mbeya region, southwestern Tanzania. Samples were selected from 17,872 persons who took part in a cohort study in 2007 and 2008. RVFV IgG status was determined by indirect immunofluorescence. Possible risk factors were analyzed using uni- and multi-variable Poisson regression models. We found a unique local maximum of RVFV IgG prevalence of 29.3% in a study site close to Lake Malawi (N = 150). The overall seroprevalence was 5.2%. Seropositivity was significantly associated with higher age, lower socio-economic status, ownership of cattle and decreased with distance to Lake Malawi. A high vegetation density, higher minimum and lower maximum temperatures were found to be associated with RVFV IgG positivity. Altitude of residence, especially on a small scale in the high-prevalence area was strongly correlated (PR 0.87 per meter, 95% CI = 0.80-0.94). Abundant surface water collections are present in the lower areas of the high-prevalence site. RVF has not been diagnosed clinically, nor an outbreak detected in the high-prevalence area. CONCLUSIONS: RVFV is probably circulating endemically in the region. The presence of cattle, dense vegetation and temperate conditions favour mosquito propagation and virus replication in the vector and seem to play major roles in virus transmission and circulation. The environmental risk-factors that we identified could serve to more exactly determine areas at risk for RVFV endemicity. |
format |
Article in Journal/Newspaper |
author |
Norbert Heinrich Elmar Saathoff Nina Weller Petra Clowes Inge Kroidl Elias Ntinginya Harun Machibya Leonard Maboko Thomas Löscher Gerhard Dobler Michael Hoelscher |
author_facet |
Norbert Heinrich Elmar Saathoff Nina Weller Petra Clowes Inge Kroidl Elias Ntinginya Harun Machibya Leonard Maboko Thomas Löscher Gerhard Dobler Michael Hoelscher |
author_sort |
Norbert Heinrich |
title |
High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. |
title_short |
High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. |
title_full |
High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. |
title_fullStr |
High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. |
title_full_unstemmed |
High seroprevalence of Rift Valley FEVER AND EVIDENCE FOR ENDEMIC circulation in Mbeya region, Tanzania, in a cross-sectional study. |
title_sort |
high seroprevalence of rift valley fever and evidence for endemic circulation in mbeya region, tanzania, in a cross-sectional study. |
publisher |
Public Library of Science (PLoS) |
publishDate |
2012 |
url |
https://doi.org/10.1371/journal.pntd.0001557 https://doaj.org/article/ef790eece9d04a34b2c8da87db36bead |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
PLoS Neglected Tropical Diseases, Vol 6, Iss 3, p e1557 (2012) |
op_relation |
http://europepmc.org/articles/PMC3313937?pdf=render https://doaj.org/toc/1935-2735 1935-2735 doi:10.1371/journal.pntd.0001557 https://doaj.org/article/ef790eece9d04a34b2c8da87db36bead |
op_doi |
https://doi.org/10.1371/journal.pntd.0001557 |
container_title |
PLoS Neglected Tropical Diseases |
container_volume |
6 |
container_issue |
3 |
container_start_page |
e1557 |
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1766345956237770752 |