Published Date: 2010-08-01 19:00:04
Subject: PRO/EDR> Hand, foot & mouth disease (07): Viet Nam
Archive Number: 20100801.2586

HAND, FOOT AND MOUTH DISEASE (07): VIET NAM
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Date: Wed 28 Jul 2010
Source: Radio The Voice of Viet Nam (VOV) News [edited]
<http://english.vovnews.vn/Home/Dengue-fever-HFMD-rampant-in-HCM-City/20107/117961.vov>


The number of cases of hand-foot-mouth disease (HFMD) has increased
quickly in Ho Chi Minh (HCM) City. Hand-foot-mouth disease has spread
to 5 districts. 340 cases were reported in June [2010] alone, up 23
percent against last year [2009], raising the number of cases in the
1st 6 months to 1640 cases, up 20 percent over the same period last
year [2009].

--
Communicated by:
PRO/MBDS
<mbds@promedmail.org>

[The activity of HFMD in some parts of Asia in 2010 is higher compared
to previous years in that the case numbers are significantly higher in
several countries and the epidemic season appears to have started
earlier this year for at least one country.

The epidemiological situation for HFMD in Asia is difficult to compare
between countries as surveillance systems, laboratory confirmation
practices, and reporting requirements differ widely between countries.
According to a recent ECDC (European Centre for Disease Prevention and
Control survey
<http://www.ecdc.europa.eu/en/healthtopics/hand_foot_and_mouth_disease/Pages/index.aspx>), as of 11 May 2010 the Chinese Ministry of Health has reported a total of 497 447 cases of HFMD (6861
severe).

Between March and April 2010, 326 365 cases of HFMD were reported,
with 215 fatal cases, compared to 267 148 cases and 96 fatalities
during the same months in 2009 -- representing a 22 percent increase
in cases and a 2-fold increase in deaths. In Shanghai there has been a
40 percent increase in cases compared to 2009 with 13 371 cases, 67
severe cases and 2 deaths reported cumulatively in 2010. The majority
of cases in China are being reported from rural communities.

Consequently, currently available data indicate that there is an
increased activity of HFMD in the region, with a higher incidence and
an earlier start of the epidemic season. Also, surveillance data from
Japan suggests that there is an increased proportion of HFMD cases
caused by enterovirus 71 (EV71) infection compared to previous years.

The reasons for the current unusual epidemiological picture of HFMD
(and specifically EV71 in Japan) are not well understood. The methods
used in Asian countries for surveillance of HFMD, as well as the
protocols for laboratory confirmation and testing do vary between
countries. Furthermore it is not known to what extent different
countries have recently adapted and/or strengthened their surveillance
for HFMD which could mean that the current observed increase is simply
due to a surveillance artefact. In order to fully understand the
current epidemiological picture of HFMD in the Asian region it would
be important to know the proportion of HFMD cases that are positive
for EV71 as well as the type of EV71 virus that is the dominant
circulating strain.

EV71 infections in Europe have been successively caused by viruses of
sub-genogroups B0, B1 and B2. A genogroup shift occurred in 1987,
after which viruses of subgenogroups C1 and C2 were detected
exclusively. This is distinct from the situation in the Asian Pacific
region, where EV71 subgenogroups B3-B5 and C4-C5 have caused large
outbreaks since 1997 (see van der Sanden et al, J Gen Virol 2010 Aug;
91(Pt 8): 1949-58
<http://vir.sgmjournals.org/cgi/content/abstract/91/8/1949>).

There are existing gaps in the knowledge about HFMD that [if they
could be filled] would contribute to a better understanding of the
situation, including:

1. Seasonality: even though most Asian countries have annual epidemics
of HFMD, it is not well understood what factors are triggering the
epidemics to start earlier (as confirmed by Japan in the present year).

2. Cyclical nature of the disease: some countries have suggested a
cyclical nature of the outbreaks every 2-3 years. The last large
outbreaks of HFMD in SE Asia occurred in 2008, and therefore the
outbreaks this year (2010) could confirm such a cyclical pattern.

For a map of the provinces of Viet Nam see
<http://upload.wikimedia.org/wikipedia/commons/f/f0/VietnameseProvincesMap.png>. The HealthMap/ProMED-mail interactive map is available
at
<http://healthmap.org/r/008O>. - Mod.CP]

See Also

Hand foot & mouth disease (06): Thailand 20100721.2451
Hand, foot & mouth disease (05): China, rural areas 20100625.2121
Hand, foot & mouth disease (04): China (GI) 20100507.1489
Hand, foot & mouth disease (03): China (Beijing) 20100416.1235
Hand, foot & mouth disease (02): China 20100412.1184
Hand foot & mouth disease: Singapore, China (HN), Viet Nam 20100329.0985
........................................cp/mj/jw
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