Browsing by Author "Chow, Angelia"

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Open Access
Chikungunya and dengue fever among hospitalized febrile patients in northern Tanzania.
(Am J Trop Med Hyg, 2012-01) Hertz, Julian T; Munishi, O Michael; Ooi, Eng Eong; Howe, Shiqin; Lim, Wen Yan; Chow, Angelia; Morrissey, Anne B; Bartlett, John A; Onyango, Jecinta J; Maro, Venance P; Kinabo, Grace D; Saganda, Wilbrod; Gubler, Duane J; Crump, John A
Consecutive febrile admissions were enrolled at two hospitals in Moshi, Tanzania. Confirmed acute Chikungunya virus (CHIKV), Dengue virus (DENV), and flavivirus infection were defined as a positive polymerase chain reaction (PCR) result. Presumptive acute DENV infection was defined as a positive anti-DENV immunoglobulin M (IgM) enzyme-linked immunsorbent assay (ELISA) result, and prior flavivirus exposure was defined as a positive anti-DENV IgG ELISA result. Among 870 participants, PCR testing was performed on 700 (80.5%). Of these, 55 (7.9%) had confirmed acute CHIKV infection, whereas no participants had confirmed acute DENV or flavivirus infection. Anti-DENV IgM serologic testing was performed for 747 (85.9%) participants, and of these 71 (9.5%) had presumptive acute DENV infection. Anti-DENV IgG serologic testing was performed for 751 (86.3%) participants, and of these 80 (10.7%) had prior flavivirus exposure. CHIKV infection was more common among infants and children than adults and adolescents (odds ratio [OR] 1.9, P = 0.026) and among HIV-infected patients with severe immunosuppression (OR 10.5, P = 0.007). CHIKV infection is an important but unrecognized cause of febrile illness in northern Tanzania. DENV or other closely related flaviviruses are likely also circulating.
Open Access
Chikungunya as a cause of acute febrile illness in southern Sri Lanka.
(PLoS One, 2013) Reller, Megan E; Akoroda, Ufuoma; Nagahawatte, Ajith; Devasiri, Vasantha; Kodikaarachchi, Wasantha; Strouse, John J; Chua, Robert; Hou, Yan'an; Chow, Angelia; Sessions, October M; Østbye, Truls; Gubler, Duane J; Woods, Christopher W; Bodinayake, Champica
BACKGROUND: Chikungunya virus (CHIKV) re-emerged in Sri Lanka in late 2006 after a 40-year hiatus. We sought to identify and characterize acute chikungunya infection (CHIK) in patients presenting with acute undifferentiated febrile illness in unstudied rural and semi-urban southern Sri Lanka in 2007. METHODOLOGY/PRINCIPAL FINDINGS: We enrolled febrile patients ≥ 2 years of age, collected uniform epidemiologic and clinical data, and obtained serum samples for serology, virus isolation, and real-time reverse-transcriptase PCR (RT-PCR). Serology on paired acute and convalescent samples identified acute chikungunya infection in 3.5% (28/797) patients without acute dengue virus (DENV) infection, 64.3% (18/28) of which were confirmed by viral isolation and/or real-time RT-PCR. No CHIKV/DENV co-infections were detected among 54 patients with confirmed acute DENV. Sequencing of the E1 coding region of six temporally distinct CHIKV isolates (April through October 2007) showed that all isolates posessed the E1-226A residue and were most closely related to Sri Lankan and Indian isolates from the same time period. Except for more frequent and persistent musculoskeletal symptoms, acute chikungunya infections mimicked DENV and other acute febrile illnesses. Only 12/797 (1.5%) patients had serological evidence of past chikungunya infection. CONCLUSIONS/SIGNIFICANCE: Our findings suggest CHIKV is a prominent cause of non-specific acute febrile illness in southern Sri Lanka.
Open Access
Emergence of Epidemic Dengue-1 Virus in the Southern Province of Sri Lanka.
(PLoS Negl Trop Dis, 2016-10) Bodinayake, Champica K; Tillekeratne, L Gayani; Nagahawatte, Ajith; Devasiri, Vasantha; Kodikara Arachichi, Wasantha; Strouse, John J; Sessions, October M; Kurukulasooriya, Ruvini; Uehara, Anna; Howe, Shiqin; Ong, Xin Mei; Tan, Sharon; Chow, Angelia; Tummalapalli, Praveen; De Silva, Aruna D; Østbye, Truls; Woods, Christopher W; Gubler, Duane J; Reller, Megan E
BACKGROUND: Dengue is a frequent cause of acute febrile illness with an expanding global distribution. Since the 1960s, dengue in Sri Lanka has been documented primarily along the heavily urbanized western coast with periodic shifting of serotypes. Outbreaks from 2005-2008 were attributed to a new clade of DENV-3 and more recently to a newly introduced genotype of DENV-1. In 2007, we conducted etiologic surveillance of acute febrile illness in the Southern Province and confirmed dengue in only 6.3% of febrile patients, with no cases of DENV-1 identified. To re-evaluate the importance of dengue as an etiology of acute febrile illness in this region, we renewed fever surveillance in the Southern Province to newly identify and characterize dengue. METHODOLOGY/PRINCIPAL FINDINGS: A cross-sectional surveillance study was conducted at the largest tertiary care hospital in the Southern Province from 2012-2013. A total of 976 patients hospitalized with acute undifferentiated fever were enrolled, with 64.3% male and 31.4% children. Convalescent blood samples were collected from 877 (89.6%). Dengue virus isolation, dengue RT-PCR, and paired IgG ELISA were performed. Acute dengue was confirmed as the etiology for 388 (39.8%) of 976 hospitalizations, with most cases (291, 75.0%) confirmed virologically and by multiple methods. Among 351 cases of virologically confirmed dengue, 320 (91.2%) were due to DENV-1. Acute dengue was associated with self-reported rural residence, travel, and months having greatest rainfall. Sequencing of selected dengue viruses revealed that sequences were most closely related to those described from China and Southeast Asia, not nearby India. CONCLUSIONS/SIGNIFICANCE: We describe the first epidemic of DENV-1 in the Southern Province of Sri Lanka in a population known to be susceptible to this serotype because of prior study. Dengue accounted for 40% of acute febrile illnesses in the current study. The emergence of DENV-1 as the foremost serotype in this densely populated but agrarian population highlights the changing epidemiology of dengue and the need for continued surveillance and prevention.