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Fulltext Endemic typhus in Singapore--a re-emerging infectious disease?

Ong AK, Tambyah PA, Ooi S, Kumarasinghe G, Chow C

Singapore Med J, 2001 Dec;42(12):549-52.
PMID: 11989574

Singapore is a modern urban city and endemic typhus is thought to be a disease of the past. This may be due to lack of specific serological testing as indirect immunoperoxidase testing using specific rickettsial antigens (U.S. Army Medical Research Unit, Institute of Medical Research, Kuala Lumpur, Malaysia) has only recently become available. In the last fourteen months, twenty-one cases of endemic typhus were diagnosed in patients hospitalised for acute febrile illnesses at the National University Hospital. We conducted a case control study to define the clinical and laboratory features of endemic typhus in Singapore.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis*
[Emerging parasitic diseases]

Weibel Galluzzo C, Wagner N, Michel Y, Jackson Y, Chappuis F

Rev Med Suisse, 2014 May 7;10(429):1008-13.
PMID: 24908745

Travels, migration and circulation of goods facilitate the emergence of new infectious diseases often unrecognized outside endemic areas. Most of emerging infections are of viral origin. Muscular Sarcocystis infection, an acute illness acquired during short trips to Malaysia, and Chagas disease, a chronic illness with long incubation period found among Latin American migrants, are two very different examples of emerging parasitic diseases. The former requires a preventive approach for travelers going to Malaysia and must be brought forth when they return with fever, myalgia and eosinophilia, while the latter requires a proactive attitude to screen Latin American migrant populations that may face difficulties in accessing care.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis*
Managing emerging diseases borne by fruit bats (flying foxes), with particular reference to henipaviruses and Australian bat lyssavirus

Mackenzie JS, Field HE, Guyatt KJ

J Appl Microbiol, 2003;94 Suppl:59S-69S.
PMID: 12675937

Since 1994, a number of novel viruses have been described from bats in Australia and Malaysia, particularly from fruit bats belonging to the genus Pteropus (flying foxes), and it is probable that related viruses will be found in other countries across the geographical range of other members of the genus. These viruses include Hendra and Nipah viruses, members of a new genus, Henipaviruses, within the family Paramyxoviridae; Menangle and Tioman viruses, new members of the Rubulavirus genus within the Paramyxoviridae; and Australian bat lyssavirus (ABLV), a member of the Lyssavirus genus in the family Rhabdoviridae. All but Tioman virus are known to be associated with human and/or livestock diseases. The isolation, disease associations and biological properties of the viruses are described, and are used as the basis for developing management strategies for disease prevention or control. These strategies are directed largely at disease minimization through good farm management practices, reducing the potential for exposure to flying foxes, and better disease recognition and diagnosis, and for ABLV specifically, the use of rabies vaccine for pre- and post-exposure prophylaxis. Finally, an intriguing and long-term strategy is that of wildlife immunization through plant-derived vaccination.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis*
Fulltext "Discovery to treatment" window in patients with smear-positive pulmonary tuberculosis

Loh LC, Codati A, Jamil M, Noor ZM, Vijayasingham P

Med J Malaysia, 2005 Aug;60(3):314-9.
PMID: 16379186

Delay in commencing treatment in patients diagnosed with smear-positive pulmonary tuberculosis (PTB) may promote the spread of PTB in the community. Socio-demographic and clinical data from 169 patients (119 retrospectively and 50 prospectively collected) treated for smear-positive PTB in our hospital Chest Clinic from June 2002 to February 2003 were analysed. One hundred and fifty eight (93.5%) patients were started on treatment in less than 7 days from the time when the report first became available while 11 (6.5%) patients had their treatment started > or = 7 days. The median 'discovery to treatment' window was 1 day (range, 0 to 24 days). Of the factors studied, longevity of symptoms, absence of fever or night sweats and having sought traditional medicine were associated with delay in treatment commencement. The urgency and importance of anti-TB treatment should be emphasized especially to patients who are inclined towards treatment with traditional medicine.
Keywords: Smear positive, pulmonary tuberculosis, treatment delay, traditional medicine, Malaysia, Seremban, Negeri Sembilan

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis
Conservation medicine and a new agenda for emerging diseases

Daszak P, Tabor GM, Kilpatrick AM, Epstein J, Plowright R

Ann N Y Acad Sci, 2004 Oct;1026:1-11.
PMID: 15604464

The last three decades have seen an alarming number of high-profile outbreaks of new viruses and other pathogens, many of them emerging from wildlife. Recent outbreaks of SARS, avian influenza, and others highlight emerging zoonotic diseases as one of the key threats to global health. Similar emerging diseases have been reported in wildlife populations, resulting in mass mortalities, population declines, and even extinctions. In this paper, we highlight three examples of emerging pathogens: Nipah and Hendra virus, which emerged in Malaysia and Australia in the 1990s respectively, with recent outbreaks caused by similar viruses in India in 2000 and Bangladesh in 2004; West Nile virus, which emerged in the New World in 1999; and amphibian chytridiomycosis, which has emerged globally as a threat to amphibian populations and a major cause of amphibian population declines. We discuss a new, conservation medicine approach to emerging diseases that integrates veterinary, medical, ecologic, and other sciences in interdisciplinary teams. These teams investigate the causes of emergence, analyze the underlying drivers, and attempt to define common rules governing emergence for human, wildlife, and plant EIDs. The ultimate goal is a risk analysis that allows us to predict future emergence of known and unknown pathogens.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis
Nipah virus: an emergent paramyxovirus causing severe encephalitis in humans

Bellini WJ, Harcourt BH, Bowden N, Rota PA

J Neurovirol, 2005 Oct;11(5):481-7.
PMID: 16287690

Nipah virus is a recently emergent paramyxovirus that is capable of causing severe disease in both humans and animals. The first outbreak of Nipah virus occurred in Malaysia and Singapore in 1999 and, more recently, outbreaks were detected in Bangladesh. In humans, Nipah virus causes febrile encephalitis with respiratory syndrome that has a high mortality rate. The reservoir for Nipah virus is believed to be fruit bats, and humans are infected by contact with infected bats or by contact with an intermediate animal host such as pigs. Person to person spread of the virus has also been described. Nipah virus retains many of the genetic and biologic properties found in other paramyxoviruses, though it also has several unique characteristics. However, the virologic characteristics that allow the virus to cause severe disease over a broad host range, and the epidemiologic, environmental and virologic features that favor transmission to humans are unknown. This review summarizes what is known about the virology, epidemiology, pathology, diagnosis and control of this novel pathogen.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis*
Fulltext Diagnostic accuracy and utility of three dengue diagnostic tests for the diagnosis of acute dengue infection in Malaysia

Chong ZL, Sekaran SD, Soe HJ, Peramalah D, Rampal S, Ng CW

BMC Infect Dis, 2020 Mar 12;20(1):210.
PMID: 32164538 DOI: 10.1186/s12879-020-4911-5

BACKGROUND: Dengue is an emerging infectious disease that infects up to 390 million people yearly. The growing demand of dengue diagnostics especially in low-resource settings gave rise to many rapid diagnostic tests (RDT). This study evaluated the accuracy and utility of ViroTrack Dengue Acute - a new biosensors-based dengue NS1 RDT, SD Bioline Dengue Duo NS1/IgM/IgG combo - a commercially available RDT, and SD Dengue NS1 Ag enzyme-linked immunosorbent assay (ELISA), for the diagnosis of acute dengue infection.
METHODS: This prospective cross-sectional study consecutively recruited 494 patients with suspected dengue from a health clinic in Malaysia. Both RDTs were performed onsite. The evaluated ELISA and reference tests were performed in a virology laboratory. The reference tests comprised of a reverse transcription-polymerase chain reaction and three ELISAs for the detection of dengue NS1 antigen, IgM and IgG antibodies, respectively. The diagnostic performance of evaluated tests was computed using STATA version 12.
RESULTS: The sensitivity and specificity of ViroTrack were 62.3% (95%CI 55.6-68.7) and 95.0% (95%CI 91.7-97.3), versus 66.5% (95%CI 60.0-72.6) and 95.4% (95%CI 92.1-97.6) for SD NS1 ELISA, and 52.4% (95%CI 45.7-59.1) and 97.7% (95%CI 95.1-99.2) for NS1 component of SD Bioline, respectively. The combination of the latter with its IgM and IgG components were able to increase test sensitivity to 82.4% (95%CI 76.8-87.1) with corresponding decrease in specificity to 87.4% (95%CI 82.8-91.2). Although a positive test on any of the NS1 assays would increase the probability of dengue to above 90% in a patient, a negative result would only reduce this probability to 23.0-29.3%. In contrast, this probability of false negative diagnosis would be further reduced to 14.7% (95%CI 11.4-18.6) if SD Bioline NS1/IgM/IgG combo was negative.
CONCLUSIONS: The performance of ViroTrack Dengue Acute was comparable to SD Dengue NS1 Ag ELISA. Addition of serology components to SD Bioline Dengue Duo significantly improved its sensitivity and reduced its false negative rate such that it missed the fewest dengue patients, making it a better point-of-care diagnostic tool. New RDT like ViroTrack Dengue Acute may be a potential alternative to existing RDT if its combination with serology components is proven better in future studies.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis
Nipah virus infection: pathology and pathogenesis of an emerging paramyxoviral zoonosis

Wong KT, Shieh WJ, Kumar S, Norain K, Abdullah W, Guarner J, et al.

Am J Pathol, 2002 Dec;161(6):2153-67.
PMID: 12466131

In 1998, an outbreak of acute encephalitis with high mortality rates among pig handlers in Malaysia led to the discovery of a novel paramyxovirus named Nipah virus. A multidisciplinary investigation that included epidemiology, microbiology, molecular biology, and pathology was pivotal in the discovery of this new human infection. Clinical and autopsy findings were derived from a series of 32 fatal human cases of Nipah virus infection. Diagnosis was established in all cases by a combination of immunohistochemistry (IHC) and serology. Routine histological stains, IHC, and electron microscopy were used to examine autopsy tissues. The main histopathological findings included a systemic vasculitis with extensive thrombosis and parenchymal necrosis, particularly in the central nervous system. Endothelial cell damage, necrosis, and syncytial giant cell formation were seen in affected vessels. Characteristic viral inclusions were seen by light and electron microscopy. IHC analysis showed widespread presence of Nipah virus antigens in endothelial and smooth muscle cells of blood vessels. Abundant viral antigens were also seen in various parenchymal cells, particularly in neurons. Infection of endothelial cells and neurons as well as vasculitis and thrombosis seem to be critical to the pathogenesis of this new human disease.

Matched MeSH terms: Communicable Diseases, Emerging/diagnosis