Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-12 (of 12 Records) |
Query Trace: Comer JA[original query] |
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Cell culture and electron microscopy for identifying viruses in diseases of unknown cause
Goldsmith CS , Ksiazek TG , Rollin PE , Comer JA , Nicholson WL , Peret TC , Erdman DD , Bellini WJ , Harcourt BH , Rota PA , Bhatnagar J , Bowen MD , Erickson BR , McMullan LK , Nichol ST , Shieh WJ , Paddock CD , Zaki SR . Emerg Infect Dis 2013 19 (6) 864-9 During outbreaks of infectious diseases or in cases of severely ill patients, it is imperative to identify the causative agent. This report describes several events in which virus isolation and identification by electron microscopy were critical to initial recognition of the etiologic agent, which was further analyzed by additional laboratory diagnostic assays. Examples include severe acute respiratory syndrome coronavirus, and Nipah, lymphocytic choriomeningitis, West Nile, Cache Valley, and Heartland viruses. These cases illustrate the importance of the techniques of cell culture and electron microscopy in pathogen identification and recognition of emerging diseases. |
Seasonal pulses of Marburg virus circulation in juvenile Rousettus aegyptiacus bats coincide with periods of increased risk of human infection
Amman BR , Carroll SA , Reed ZD , Sealy TK , Balinandi S , Swanepoel R , Kemp A , Erickson BR , Comer JA , Campbell S , Cannon DL , Khristova ML , Atimnedi P , Paddock CD , Kent Crockett RJ , Flietstra TD , Warfield KL , Unfer R , Katongole-Mbidde E , Downing R , Tappero JW , Zaki SR , Rollin PE , Ksiazek TG , Nichol ST , Towner JS . PLoS Pathog 2012 8 (10) e1002877 Marburg virus (family Filoviridae) causes sporadic outbreaks of severe hemorrhagic disease in sub-Saharan Africa. Bats have been implicated as likely natural reservoir hosts based most recently on an investigation of cases among miners infected in 2007 at the Kitaka mine, Uganda, which contained a large population of Marburg virus-infected Rousettus aegyptiacus fruit bats. Described here is an ecologic investigation of Python Cave, Uganda, where an American and a Dutch tourist acquired Marburg virus infection in December 2007 and July 2008. More than 40,000 R. aegyptiacus were found in the cave and were the sole bat species present. Between August 2008 and November 2009, 1,622 bats were captured and tested for Marburg virus. Q-RT-PCR analysis of bat liver/spleen tissues indicated approximately 2.5% of the bats were actively infected, seven of which yielded Marburg virus isolates. Moreover, Q-RT-PCR-positive lung, kidney, colon and reproductive tissues were found, consistent with potential for oral, urine, fecal or sexual transmission. The combined data for R. aegyptiacus tested from Python Cave and Kitaka mine indicate low level horizontal transmission throughout the year. However, Q-RT-PCR data show distinct pulses of virus infection in older juvenile bats ( approximately six months of age) that temporarily coincide with the peak twice-yearly birthing seasons. Retrospective analysis of historical human infections suspected to have been the result of discrete spillover events directly from nature found 83% (54/65) events occurred during these seasonal pulses in virus circulation, perhaps demonstrating periods of increased risk of human infection. The discovery of two tags at Python Cave from bats marked at Kitaka mine, together with the close genetic linkages evident between viruses detected in geographically distant locations, are consistent with R. aegyptiacus bats existing as a large meta-population with associated virus circulation over broad geographic ranges. These findings provide a basis for developing Marburg hemorrhagic fever risk reduction strategies. |
Characterization of Nipah virus from outbreaks in Bangladesh, 2008-2010
Lo MK , Lowe L , Hummel KB , Sazzad HM , Gurley ES , Hossain MJ , Luby SP , Miller DM , Comer JA , Rollin PE , Bellini WJ , Rota PA . Emerg Infect Dis 2012 18 (2) 248-55 Nipah virus (NiV) is a highly pathogenic paramyxovirus that causes fatal encephalitis in humans. The initial outbreak of NiV infection occurred in Malaysia and Singapore in 1998-1999; relatively small, sporadic outbreaks among humans have occurred in Bangladesh since 2001. We characterized the complete genomic sequences of identical NiV isolates from 2 patients in 2008 and partial genomic sequences of throat swab samples from 3 patients in 2010, all from Bangladesh. All sequences from patients in Bangladesh comprised a distinct genetic group. However, the detection of 3 genetically distinct sequences from patients in the districts of Faridpur and Gopalganj indicated multiple co-circulating lineages in a localized region over a short time (January-March 2010). Sequence comparisons between the open reading frames of all available NiV genes led us to propose a standardized protocol for genotyping NiV; this protcol provides a simple and accurate way to classify current and future NiV sequences. |
Date palm sap linked to Nipah virus outbreak in Bangladesh, 2008
Rahman MA , Hossain MJ , Sultana S , Homaira N , Khan SU , Rahman M , Gurley ES , Rollin PE , Lo MK , Comer JA , Lowe L , Rota PA , Ksiazek TG , Kenah E , Sharker Y , Luby SP . Vector Borne Zoonotic Dis 2012 12 (1) 65-72 INTRODUCTION: We investigated a cluster of patients with encephalitis in the Manikgonj and Rajbari Districts of Bangladesh in February 2008 to determine the etiology and risk factors for disease. METHODS: We classified persons as confirmed Nipah cases by the presence of immunoglobulin M antibodies against Nipah virus (NiV), or by the presence of NiV RNA or by isolation of NiV from cerebrospinal fluid or throat swabs who had onset of symptoms between February 6 and March 10, 2008. We classified persons as probable cases if they reported fever with convulsions or altered mental status, who resided in the outbreak areas during that period, and who died before serum samples were collected. For the case-control study, we compared both confirmed and probable Nipah case-patients to controls, who were free from illness during the reference period. We used motion-sensor-infrared cameras to observe bat's contact of date palm sap. RESULTS: We identified four confirmed and six probable case-patients, nine (90%) of whom died. The median age of the cases was 10 years; eight were males. The outbreak occurred simultaneously in two communities that were 44 km apart and separated by a river. Drinking raw date palm sap 2-12 days before illness onset was the only risk factor most strongly associated with the illness (adjusted odds ratio 25, 95% confidence intervals 3.3-infinity, p<0.001). Case-patients reported no history of physical contact with bats, though community members often reported seeing bats. Infrared camera photographs showed that Pteropus bats frequently visited date palm trees in those communities where sap was collected for human consumption. CONCLUSION: This is the second Nipah outbreak in Bangladesh where date palm sap has been implicated as the vehicle of transmission. Fresh date palm sap should not be drunk, unless effective steps have been taken to prevent bat access to the sap during collection. |
Dynamics of hantavirus infection in Peromyscus leucopus of central Pennsylvania
Luong LT , Vigliotti BA , Campbell S , Comer JA , Mills JN , Hudson PJ . Vector Borne Zoonotic Dis 2011 11 (11) 1459-64 Hantaviruses are distributed throughout the United States and are the etiologic agents for hantavirus pulmonary syndrome and hemorrhagic fever with renal syndrome. Hantavirus genotypes and epidemiologic patterns vary spatially across the United States. While several longitudinal studies have been performed in the western United States, little is known about the virus in the eastern United States. We undertook a longitudinal study of hantaviruses in the primary rodent reservoir host in central Pennsylvania, Peromyscus leucopus. Prevalence of hantavirus antibodies varied both by year and site, but was not correlated with host abundance. Males were significantly more likely to have antibodies to a hantavirus than females, and both antibody sero-conversion and antibody prevalence increased with mass class (indicator for age). Our findings suggest that one or more hantaviruses are present and circulating among P. leucopus of central Pennsylvania, and understanding the dynamics in this region could help prevent zoonotic transmission to humans. Our aim was to describe the differences in epizootiology of hantavirus infection in rodents from various geographical locations to enable improved analysis of the risk of rodent-to-human transmission and obtain insights that may indicate improved means of disease intervention. |
Ancient ancestry of KFDV and AHFV revealed by complete genome analyses of viruses isolated from ticks and mammalian hosts.
Dodd KA , Bird BH , Khristova ML , Albarino CG , Carroll SA , Comer JA , Erickson BR , Rollin PE , Nichol ST . PLoS Negl Trop Dis 2011 5 (10) e1352 BACKGROUND: Alkhurma hemorrhagic fever virus (AHFV) and Kyasanur forest disease virus (KFDV) cause significant human disease and mortality in Saudi Arabia and India, respectively. Despite their distinct geographic ranges, AHFV and KFDV share a remarkably high sequence identity. Given its emergence decades after KFDV, AHFV has since been considered a variant of KFDV and thought to have arisen from an introduction of KFDV to Saudi Arabia from India. To gain a better understanding of the evolutionary history of AHFV and KFDV, we analyzed the full length genomes of 16 AHFV and 3 KFDV isolates. METHODOLOGY/PRINCIPAL FINDINGS: Viral genomes were sequenced and compared to two AHFV sequences available in GenBank. Sequence analyses revealed higher genetic diversity within AHFVs isolated from ticks than human AHFV isolates. A Bayesian coalescent phylogenetic analysis demonstrated an ancient divergence of AHFV and KFDV of approximately 700 years ago. CONCLUSIONS/SIGNIFICANCE: The high sequence diversity within tick populations and the presence of competent tick vectors in the surrounding regions, coupled with the recent identification of AHFV in Egypt, indicate possible viral range expansion or a larger geographic range than previously thought. The divergence of AHFV from KFDV nearly 700 years ago suggests other AHFV/KFDV-like viruses might exist in the regions between Saudi Arabia and India. Given the human morbidity and mortality associated with these viruses, these results emphasize the importance of more focused study of these significant public health threats. |
Kyasanur Forest Disease virus Alkhurma subtype in ticks, Najran Province, Saudi Arabia.
Mahdi M , Erickson BR , Comer JA , Nichol ST , Rollin PE , Almazroa MA , Memish ZA . Emerg Infect Dis 2011 17 (5) 945-7 TO THE EDITOR: The lineage of Kyasanur Forest disease virus (KFDV) found in the Kingdom of Saudi Arabia is commonly referred to as Alkhurma hemorrhagic fever virus (AHFV). This virus was first isolated from a specimen collected in 1994 from a butcher living in Makkah Province, who was hospitalized for a hemorrhagic fever from which he died (1). The virus was assigned to the genus Flavivirus on the basis of reactivity with genus-specific monoclonal antibodies and sequencing of a fragment of the nonstructural 5 (NS5) gene, which showed >89% identity with KFDV. Ten other cases were confirmed among patients who had leukopenia, thrombocytopenia, and elevated liver enzymes. Observations of patients in the original study or in a subsequent analysis (2) suggested that Alkhurma hemorrhagic fever (AHF) disease was associated with contact with blood from infected animals, bites from infected ticks, or the drinking of raw milk. However, the exact mode of transmission to humans has still not been fully elucidated. More recently, AHFV RNA was detected in a single pool of sand tampans (Ornithodoros savignyi, soft ticks), collected in western Saudi Arabia (3), which suggests a link with these ticks. |
Nipah virus outbreak with person-to-person transmission in a district of Bangladesh, 2007
Homaira N , Rahman M , Hossain MJ , Epstein JH , Sultana R , Khan MS , Podder G , Nahar K , Ahmed B , Gurley ES , Daszak P , Lipkin WI , Rollin PE , Comer JA , Ksiazek TG , Luby SP . Epidemiol Infect 2010 138 (11) 1630-6 In February 2007 an outbreak of Nipah virus (NiV) encephalitis in Thakurgaon District of northwest Bangladesh affected seven people, three of whom died. All subsequent cases developed illness 7-14 days after close physical contact with the index case while he was ill. Cases were more likely than controls to have been in the same room (100% vs. 9.5%, OR undefined, P<0.001) and to have touched him (83% vs. 0%, OR undefined, P<0.001). Although the source of infection for the index case was not identified, 50% of Pteropus bats sampled from near the outbreak area 1 month after the outbreak had antibodies to NiV confirming the presence of the virus in the area. The outbreak was spread by person-to-person transmission. Risk of NiV infection in family caregivers highlights the need for infection control practices to limit transmission of potentially infectious body secretions. |
High diversity and ancient common ancestry of lymphocytic choriomeningitis virus
Albarino CG , Palacios G , Khristova ML , Erickson BR , Carroll SA , Comer JA , Hui J , Briese T , St George K , Ksiazek TG , Lipkin WI , Nichol ST . Emerg Infect Dis 2010 16 (7) 1093-100 Lymphocytic choriomeningitis virus (LCMV) is the prototype of the family Arenaviridae. LCMV can be associated with severe disease in humans, and its global distribution reflects the broad dispersion of the primary rodent reservoir, the house mouse (Mus musculus). Recent interest in the natural history of the virus has been stimulated by increasing recognition of LCMV infections during pregnancy, and in clusters of LCMV-associated fatal illness among tissue transplant recipients. Despite its public health importance, little is known regarding the genetic diversity or distribution of virus variants. Genomic analysis of 29 LCMV strains collected from a variety of geographic and temporal sources showed these viruses to be highly diverse. Several distinct lineages exist, but there is little correlation with time or place of isolation. Bayesian analysis estimates the most recent common ancestor to be 1,000-5,000 years old, and this long history is consistent with complex phylogeographic relationships of the extant virus isolates. |
Sin Nombre virus-specific immunoglobulin M and G kinetics in hantavirus pulmonary syndrome and the role played by serologic responses in predicting disease outcome
Macneil A , Comer JA , Ksiazek TG , Rollin PE . J Infect Dis 2010 202 (2) 242-6 BACKGROUND: Sin Nombre virus (SNV) is the primary cause of hantavirus pulmonary syndrome (HPS) in the United States. Although other studies have demonstrated a possible association between neutralizing antibody titers and the severity of HPS, the exact nature of serologic responses and their association with outcomes have not been fully characterized. METHODS: We examined immunoglobulin M (IgM) and immunoglobulin G (IgG) serologic responses in 94 clinical samples from 81 patients with confirmed HPS. We further compared a subset of 31 patients with fatal HPS and 20 surviving patients for whom samples were available within a week after the onset of HPS. RESULTS: SNV-specific IgM antibodies displayed a trend suggesting an early peak, whereas IgG antibody values peaked later. Among individuals with samples from the first week after the onset of HPS, all surviving patients had SNV-specific IgG responses, compared with <50% of patients with fatal HPS, and the distribution of IgG responses was significantly higher in surviving patients. CONCLUSIONS: Production of SNV-specific IgM antibodies occurs early during the clinical course of HPS, whereas production of IgG antibodies may be more protracted. The presence and overall distribution of higher IgG antibody titers in surviving patients with HPS suggests that production of SNV-specific IgG may be a strong predictor of favorable outcomes. |
Recurrent zoonotic transmission of Nipah virus into humans, Bangladesh, 2001-2007
Luby SP , Hossain MJ , Gurley ES , Ahmed BN , Banu S , Khan SU , Homaira N , Rota PA , Rollin PE , Comer JA , Kenah E , Ksiazek TG , Rahman M . Emerg Infect Dis 2009 15 (8) 1229-35 Human Nipah outbreaks recur in a specific region and time of year in Bangladesh. Fruit bats are the reservoir host for Nipah virus. We identified 23 introductions of Nipah virus into human populations in central and northwestern Bangladesh from 2001 through 2007. Ten introductions affected multiple persons (median 10). Illness onset occurred from December through May but not every year. We identified 122 cases of human Nipah infection. The mean age of case-patients was 27 years; 87 (71%) died. In 62 (51%) Nipah virus-infected patients, illness developed 5-15 days after close contact with another Nipah case-patient. Nine (7%) Nipah case-patients transmitted virus to others. Nipah case-patients who had difficulty breathing were more likely than those without respiratory difficulty to transmit Nipah (12% vs. 0%, p = 0.03). Although a small minority of infected patients transmit Nipah virus, more than half of identified cases result from person-to-person transmission. Interventions to prevent virus transmission from bats to humans and from person to person are needed. |
Isolation of genetically diverse Marburg viruses from Egyptian fruit bats
Towner JS , Amman BR , Sealy TK , Carroll SA , Comer JA , Kemp A , Swanepoel R , Paddock CD , Balinandi S , Khristova ML , Formenty PB , Albarino CG , Miller DM , Reed ZD , Kayiwa JT , Mills JN , Cannon DL , Greer PW , Byaruhanga E , Farnon EC , Atimnedi P , Okware S , Katongole-Mbidde E , Downing R , Tappero JW , Zaki SR , Ksiazek TG , Nichol ST , Rollin PE . PLoS Pathog 2009 5 (7) e1000536 In July and September 2007, miners working in Kitaka Cave, Uganda, were diagnosed with Marburg hemorrhagic fever. The likely source of infection in the cave was Egyptian fruit bats (Rousettus aegyptiacus) based on detection of Marburg virus RNA in 31/611 (5.1%) bats, virus-specific antibody in bat sera, and isolation of genetically diverse virus from bat tissues. The virus isolates were collected nine months apart, demonstrating long-term virus circulation. The bat colony was estimated to be over 100,000 animals using mark and re-capture methods, predicting the presence of over 5,000 virus-infected bats. The genetically diverse virus genome sequences from bats and miners closely matched. These data indicate common Egyptian fruit bats can represent a major natural reservoir and source of Marburg virus with potential for spillover into humans. |
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