Re: Philippines: International help sought to diagnose the deaths of 7 people who died after eating horsemeat that died of unknown cause
Re: Philippines: International help sought to diagnose the deaths of 7 people who died after eating horsemeat that died of unknown cause
Published Date: 2014-11-11 13:39:25
Subject: PRO/AH/EDR> Henipavirus - Philippines: (SK) RFI
Archive Number: 20141111.2944610
HENIPAVIRUS - PHILIPPINES: (SULTAN KUDARAT) REQUEST FOR INFORMATION
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Date: Fri 7 Nov 2014
Source: Emerging Infectious Diseases journal [summ., edited]
http://wwwnc.cdc.gov/eid/article/21/2/14-1433_article
ref: Ching PKG, de los Reyes CV, Sucaldito MN, et al. Outbreak of henipavirus infection, Philippines, 2014. Emerg Infect Dis. 2014; 21(2) [published ahead of print]
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Abstract
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During 2014, henipavirus infection caused severe illness among humans and horses in southern Philippines; fatality rates among humans were high. Horse-to-human and human-to-human transmission occurred. The most likely source of horse infection was fruit bats. Ongoing surveillance is needed for rapid diagnosis, risk factor investigation, control measure implementation, and further virus characterization.
Background
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Henipaviruses belong to a genus of recently emerging viruses within the family _Paramyxoviridae_ and include 2 zoonotic members: Hendra virus (HeV) and Nipah virus (NiV). HeV was first described in Australia in 1994, when it caused an outbreak of severe acute respiratory diseases that led to a high mortality rate among horses. Subsequently, several sporadic cases of HeV infection have occurred in horses in Australia; transmission to humans has occurred and the fatality rate was high. NiV was first recognized as a human pathogen in peninsular Malaysia in 1998. This outbreak among pig farmers and abattoir workers exposed to infected swine secretions was associated with severe encephalitic illness and a high fatality rate. Subsequently, NiV emerged as a major public health problem in Bangladesh and India.
The natural reservoir of both viruses is pteropid bats, which harbor the viruses but do not show clinical illness. Virus transmission from bats to domestic animals is thought to be through pasture or feed contaminated by bat urine, feces, or other excretions. Human-to-human transmission of NiV also occurs.
The study
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On 2 Apr 2014, the Philippine National Epidemiology Center received a report of human deaths in 2 villages, Tinalon and Midtungok, in the municipality of Senator Ninoy Aquino, province of Sultan Kudarat, island of Mindanao. The villages are about 15 km [9.3 mi] apart, and the provincial referral hospital is in Isulan, 80 km [49.7 mi] away. An outbreak investigation led by the National Epidemiology Center identified additional human deaths and nonfatal infections and concurrent neurologic disease and sudden deaths in several horses, all of which were subsequently consumed by villagers. On 12 May 2014, the Philippine government asked the World Health Organization for further outbreak investigation assistance.
During 22-24 May 2014, a combined team from the Philippine Department of Health, Department of Agriculture, and the World Health Organization interviewed persons who survived, those with suspected cases, and family members of the deceased and conducted focus group interviews with other persons in affected villages. Key informants from local human and animal health agencies were also interviewed, and hospital records for persons with suspected cases were reviewed. We defined a human case as illness in any person with an epidemiologic link to the municipality of Senator Ninoy Aquino and who had experienced acute encephalitis syndrome, severe influenza-like illness (ILI), or meningitis during 3 Mar-24 May 2014.
Conclusions
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Clinical presentations, epidemiologic findings, and serologic results suggest that the virus causing this outbreak was a henipavirus. It was most likely NiV or a virus that is antigenically and genetically closely related to NiV.
Epidemiologic data suggest that the most common route of virus transmission to humans was direct exposure to infected horses, contact with contaminated body fluids during slaughtering of sick horses, and/or consumption of undercooked meat from infected horses. However, for at least 5 cases, clinical and epidemiologic evidence suggest direct human-to-human virus transmission. No protective equipment was used by those who cared for case-patients in the home, and health care workers used gloves and a face mask but not eye protection. The evidence of human-to-human transmission in this outbreak confirms the need for preventative measures in home care and health care settings.
Although the source of the horse infections is unclear, on the basis of the known ecology of henipaviruses, the most likely source is fruit bats (family _Pteropodidae_). Bats belonging to this family were reported near at least 1 of the 2 villages.
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[Although this is the 1st report that ProMED-mail has posted explicitly suggesting that Nipah virus infections were involved in these human and equine cases in the Philippines, there were earlier posts this year (2014) of undiagnosed human and equine cases of an undiagnosed disease in Sultan Kudarat province that undoubtedly are the same ones reported above.
In the earlier report, Mod.LL suggested that a Hendra-like virus might be involved. Nipah virus, which is endemic in south east and south Asia, seems more likely to be the etiological agent responsible for this outbreak than Hendra virus, which is endemic in Australia. Genomic analysis shows the viruses isolated from the outbreak are closely related to Nipah virus as do serological tests from sampled surviving humans.