Hepatitis: Linthicum KJ

Anyamba A, Chretien JP, Small J, Tucker CJ, Formenty PB, Richardson JH, Britch SC, Schnabel DC, Erickson RL, Linthicum KJ. · National Aeronautics and Space Administration Goddard Space Flight Center, Biospheric Sciences Branch, Code 614.4, Greenbelt, MD 20771, USA. · Proc Natl Acad Sci U S A. · Pubmed #19144928 links to  free full text

Abstract: El Niño/Southern Oscillation related climate anomalies were analyzed by using a combination of satellite measurements of elevated sea-surface temperatures and subsequent elevated rainfall and satellite-derived normalized difference vegetation index data. A Rift Valley fever (RVF) risk mapping model using these climate data predicted areas where outbreaks of RVF in humans and animals were expected and occurred in the Horn of Africa from December 2006 to May 2007. The predictions were subsequently confirmed by entomological and epidemiological field investigations of virus activity in the areas identified as at risk. Accurate spatial and temporal predictions of disease activity, as it occurred first in southern Somalia and then through much of Kenya before affecting northern Tanzania, provided a 2 to 6 week period of warning for the Horn of Africa that facilitated disease outbreak response and mitigation activities. To our knowledge, this is the first prospective prediction of a RVF outbreak.

Anyamba A, Linthicum KJ, Tucker CJ. · NASA Goddard Space Flight Center, Greenbelt, MD, USA. · Cad Saude Publica. · Pubmed #11426274 links to  free full text

Abstract: All known Rift Valley fever(RVF) outbreaks in Kenya from 1950 to 1998 followed periods of abnormally high rainfall. On an interannual scale, periods of above normal rainfall in East Africa are associated with the warm phase of the El Niño/Southern Oscillation (ENSO) phenomenon. Anomalous rainfall floods mosquito-breeding habitats called dambos, which contain transovarially infected mosquito eggs. The eggs hatch Aedes mosquitoes that transmit the RVF virus preferentially to livestock and to humans as well. Analysis of historical data on RVF outbreaks and indicators of ENSO (including Pacific and Indian Ocean sea surface temperatures and the Southern Oscillation Index) indicates that more than three quarters of the RVF outbreaks have occurred during warm ENSO event periods. Mapping of ecological conditions using satellite normalized difference vegetation index (NDVI) data show that areas where outbreaks have occurred during the satellite recording period (1981-1998) show anomalous positive departures in vegetation greenness, an indicator of above-normal precipitation. This is particularly observed in arid areas of East Africa, which are predominantly impacted by this disease. These results indicate a close association between interannual climate variability and RVF outbreaks in Kenya.

Linthicum KJ, Anyamba A, Tucker CJ, Kelley PW, Myers MF, Peters CJ. · Department of Defense, Global Emerging Infections System, Division of Preventive Medicine, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA. · Science. · Pubmed #10411500 links to  free full text

Abstract: All known Rift Valley fever virus outbreaks in East Africa from 1950 to May 1998, and probably earlier, followed periods of abnormally high rainfall. Analysis of this record and Pacific and Indian Ocean sea surface temperature anomalies, coupled with satellite normalized difference vegetation index data, shows that prediction of Rift Valley fever outbreaks may be made up to 5 months in advance of outbreaks in East Africa. Concurrent near-real-time monitoring with satellite normalized difference vegetation data may identify actual affected areas.

Anyamba A, Chretien JP, Formenty PB, Small J, Tucker CJ, Malone JL, El Bushra H, Martin V, Linthicum KJ. · No affiliation provided · Emerg Infect Dis. · Pubmed #16710979 No free full text.

This publication has no abstract.

He J, Innis BL, Shrestha MP, Clayson ET, Scott RM, Linthicum KJ, Musser GG, Gigliotti SC, Binn LN, Kuschner RA, Vaughn DW. · Walter Reed Army Institute of Research, Silver Spring, Maryland, USA. · J Clin Microbiol. · Pubmed #16517936 links to  free full text

This publication has no abstract.

He J, Innis BL, Shrestha MP, Clayson ET, Scott RM, Linthicum KJ, Musser GG, Gigliotti SC, Binn LN, Kuschner RA, Vaughn DW. · Walter Reed Army Institute of Research, Silver Spring, Maryland, USA. · J Clin Microbiol. · Pubmed #12454141 links to  free full text

Abstract: Hepatitis E virus (HEV) is an important cause of enterically transmitted hepatitis in developing countries. Sporadic autochthonous cases of hepatitis E have been reported recently in the United States and other industrialized countries. The source of HEV infection in these cases is unknown; zoonotic transmission has been suggested. Antibodies to HEV have been detected in many animals in areas where HEV is endemic and in domestic swine and rats in the United States. There is evidence supporting HEV transmission between swine and humans. Nevertheless, HEV has not been detected in wild rodents. We tested murid rodents and house shrews trapped in Nepal's Kathmandu Valley, where hepatitis E is hyperendemic, for HEV infection. The most commonly trapped species was Rattus rattus brunneusculus. Serum samples from 675 animals were tested for immunoglobulin G against HEV by enzyme-linked immunosorbent assay; 78 (12%) were positive, indicating acute or past infection. Antibody prevalence was higher among R. rattus brunneusculus and Bandicota bengalensis than in Suncus murinus. Forty-four specimens from 78 antibody-positive animals had sufficient residual volume for detection of HEV RNA (viremia) by reverse transcription-PCR. PCR amplification detected four animals (9%; three were R. rattus brunneusculus and one was B. bengalensis) with viremia. Phylogenetic analysis of the four genome sequences (405 bp in the capsid gene) recovered showed that they were identical, most closely related to two human isolates from Nepal (95 and 96% nucleotide homology, respectively), and distinct from HEV sequences isolated elsewhere. These data prove that certain peridomestic rodents acquire HEV in the wild and suggest that cross-species transmission occurs, with rodents serving as a virus reservoir for humans.