MERS CoV infection - ecological investigations (Examines influence of exotic animal markets)

[Emily]

http://www.ijidonline.com/article/S1...545-1/fulltext

MERS CoV infection - ecological investigations
S.F. Fagbo, A. Durosinloun, A. Ramadan, A. Oni, M. Asmari, A. Asaigul, B. Jinadu, W. Siddiqui
International Journal of Infectious Diseases - April 2014 (Vol. 21Supplement 1, Page 35, DOI: 10.1016/j.ijid.2014.03.486)

...

Results: Contrary to the media frenzy about camels and MERS CoV transmission, rarely did any of the cases we investigated have exposure to camels. In the Ahsa outbreak in the Eastern region of Saudi Arabia, a large subset of the patients investigated were initially reported as having no animal exposure. We observed the unrestricted mixing of wild and domestic animals in animal markets in a manner that could definitely facilitate repeated pathogen spillover and emergence. Additionally, some of these animals were overtly sick. Evidence for trading in bats was also documented. Wild animals were transported to the markets over large distances in questionable welfare conditions that may also encourage disease emergence.

...

PII: S1201-9712(14)00545-1
doi:10.1016/j.ijid.2014.03.486
? 2014 Published by Elsevier Inc.

Hat tip to Crof.

[IanM]

Re: MERS CoV infection - ecological investigations (Examines influence of exotic animal markets)

The Hafr Al-Batin mention here makes no sense. There has been a detailed report only recently showing extensive camel exposure.

http://www.ncbi.nlm.nih.gov/pubmed/24699184

"One 225 of the differences between primary cases and secondary
cases 226 in MERS-CoV clusters is that primary cases usually acquire
infection 227 through contact with non-human sources of the virus.23"

"It seems that the timing of 252 the Hafr Al-Batin sequence divergence is consistent with the annual 253 fair and animal movement."

This message seems very difficult for people to comprehend.

Rarely is anything black-or-white, all-or-nothing, 1-or-0, in a biological system. Extensive camel contact is not necessary for this virus to spread. Jeddah-2014 has hit us over the head with this, although it was plain to see beforehand, that h2h spread is the MAJOR method of transmission of MERS-CoV to date. However inefficient that spread is.

I take paracetamol for a headache (I'll need some now) but headaches are not caused by paracetamol. Finding other animals in markets that *could* spread MERS-CoV does not mean they did. The abstract should have noted whether the lab-confirmed cases being investigated actually had any contact with these bats or animal markets

Rare introduction from camels, a known host, seems to be all that is needed in the context of poor infection prevention and control.

[Emily]

Re: MERS CoV infection - ecological investigations (Examines influence of exotic animal markets)

The abstract should have noted whether the lab-confirmed cases being investigated actually had any contact with these bats or animal markets

I agree & thanks for the heads up about the new article, but I don't think your headache is going away anytime soon.

http://wwwnc.cdc.gov/eid/article/20/...22_article.htm

Unraveling the mysteries of Middle East respiratory syndrome coronavirus. Emerg Infect Dis [Internet]. 2014 Jun
John T. WatsonComments to Author , Aron J. Hall, Dean D. Erdman, David L Swerdlow, and Susan I. Gerber
Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

http://dx.doi.org/10.3201/eid2006.140322

DOI: 10.3201/eid2006.140322

...

This month?s issue of Emerging Infectious Diseases presents results of a study that provides evidence of MERS-CoV in dromedary camels in Egypt (18). Only 3 other reports of MERS-CoV detection in animals have been published: 1 in a bat and 2 in camels (11,12,19). However, these reports were based on limited genetic information. In contrast, on the basis of their sequence analysis of nearly the entire viral genome that showed >99% nt sequence identity with human MERS-CoV, Chu et al. provide the most compelling evidence thus far of MERS-CoV infection in dromedary camels (18). Although the authors also found neutralizing antibodies to MERS-CoV (or a MERS-like CoV) in most of the camels, they did not find serologic evidence of infection in the abattoir workers who had contact with the infected animals. This finding leaves key questions about zoonotic transmission unanswered. Most notably, it remains unclear whether zoonotic transmission of MERS-CoV occurs between camels and humans and, if so, what the directionality and risk factors are for such transmission. These lingering gaps in knowledge about MERS-CoV emphasize the need for more epidemiologic study to determine risk factors for human infection, more population-level data on the prevalence of MERS-CoV in camels, risk factors for infection and shedding in camels, and continued vigilance for other possible sources of infection. Also, the camels tested were in Egypt and were locally reared or imported from Sudan or Ethiopia, countries in which no cases have been identified in humans. Thus, the geographic area for surveillance should be widened beyond the Arabian Peninsula and include eastern Africa, which is a source for importation of dromedary camels. This study emphasizes the need to further define exposure information for all MERS-CoV cases regarding camels and other animals, as well as exposure to ill humans who might have undetected MERS-CoV infections. Understanding the role of dromedary camels and possibly other animals in transmission of MERS-CoV to humans remains a priority for future investigation to enable development of targeted control measures and prevent future cases and deaths from this emerging pathogen.

I'm still not convinced that camels are the source of human MERS-CoV.

http://www.eurosurveillance.org/View...rticleId=20811

Eurosurveillance, Volume 19, Issue 20, 22 May 2014
Letters
Authors? reply: Middle East respiratory syndrome coronavirus (MERS-CoV) in dromedary camels: are dromedary camels a reservoir for MERS-CoV?
N Nowotny ()1,2, J Kolodziejek1

...

Human infections resulting from (probably very close direct) contact with acutely infected camels have been shown [8], and such cases may be the source of limited human-to-human transmissions. However, the vast majority of MERS-CoV transmissions seem to occur within families [15], in the community [16] and in healthcare facilities [15], which especially raise a serious concern. In addition, in a growing number of infected people, the source of infection remains unclear.