Just a rather long update on the polio situation in the DR. I think it will answer most of your questions. It is taken from Promedmail - an international surveillance service that among others the CDC use. This means that the language is a bit technical here and there. The short summary would be: No need for alarm, but if you are not already immunized, get it sorted out before you go.
As for Dengue - there has been about 20 or 30 cases confirmed in European tourists returning home from the DR. However, Dengue is almost everywhere - including from time to time the States. Use insect repellent. At a resort the risk is not very large. Dengue mainly spreads in cities, because the dengue mosquitos breed in dirty, stagnant water.
OK - here it goes from Promedmail:
Outbreak of Sabin Vaccine-Derived Polio in Dominican Republic and Haiti
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WASHINGTON: The Pan American Health Organization (PAHO) has 16
epidemiologists supporting the Ministries of Health of the Dominican
Republic and Haiti in the investigation of a current outbreak of
poliomyelitis and in carrying out vaccination campaigns on the island of
Hispaniola, which both countries share, according to Dr. Ciro de Quadros,
who directs the Organization's Division of Vaccines and Immunization.
The outbreak in Dominican Republic and Haiti has raised serious concerns
because the Western Hemisphere has been free of wild poliovirus circulation
since 1991, and because the virus identified is an unusual derivative of
the Sabin type 1 oral poliovirus vaccine (OPV). PAHO convened a group of
immunization experts yesterday [Thu 7 Dec 2000] to discuss these concerns
raised by the outbreak.
In a report presented at the meeting of experts, PAHO officials said that
because of the concern of possible pesticide poisoning in Constanza, an
agricultural area of the Dominican Republic, an active case search was
initiated after a case of acute flaccid paralysis was reported in early
October, and 2 more paralysis cases were found. Lab testing showed that an
unusual strain of Sabin Type 1 poliovirus had been isolated, and 18
possible cases were being investigated, with 14 of them being clinically
compatible with poliomyelitis. The cases are located in the provinces of La
Vega, Santiago, and Mons Nouel, with 13 concentrated in Constanza City.
Except for one case, all the others are epidemiologically linked, the
report said.
In Haiti, a single laboratory-confirmed case due to the derived type 1
virus has been reported to date, in the town of Nan Citron, with paralysis
onset on 10 Aug 2000. The Ministries of Health of the Dominican Republic
and Haiti, with the assistance of the PAHO and the Centers for Disease
Control and Prevention (CDC), are investigating the outbreak to determine
the extent of spread and evaluate the reasons for the outbreak.
Experts from PAHO have been sent to Hispaniola to work with local
authorities in the investigation, and aggressive control measures have
already been put in place. A mass vaccination campaign with OPV has already
started in the Dominican Republic, initially covering the 3 provinces with
suspected cases, followed shortly by the rest of the country. In Haiti, 3
nationwide vaccination rounds with OPV are planned for January, February
and March [2001].
After intensive case-finding activities, no other cases have been found so
far, Dr. de Quadros said, and all of the cases were either unvaccinated or
had not had their complete doses of polio vaccine. The essential factor for
control of circulating OPV-derived viruses is the same as that required to
control wild poliovirus circulation: achieving and maintaining high
vaccination coverage, Dr. de Quadros said. "No evidence for circulation of
OPV-derived virus has ever been found in any area with high coverage," he
added.
The experts at the PAHO meeting, who included Dr. D.A. Henderson, leader of
the global smallpox eradication campaign and chairman of PAHO's Technical
Advisory Group, discussed the steps being taken to determine the causes of
the virus reversion, determine the extent of transmission, control the
outbreak, and [identify] possible implications for the global polio
eradication campaign, which aims to rid the planet of the disease by 2005.
Dr. Henderson said, "We will continue studying this outbreak, but meanwhile
we need to proceed ahead with the global eradication campaign. This
episode, an outbreak from a virus derived from a vaccine strain that made a
transition 2 years ago, occurred in an area where vaccination levels were
low. The lesson is clear. We must keep vaccination coverage high until we
get to the zero point of stopping polio transmission, we must undertake
additional studies, and we must keep everyone updated on this situation."
Since the Global Polio Eradication Initiative was launched in 1988, the
number of polio cases globally has dropped by over 95%, from an estimated
350 000 in 1988 to 7094 reported in 1999. There have only been 1481
confirmed cases of polio so far this year. The WHO European Region (made up
of 51 countries, including the Commonwealth of Independent States) has not
had any new cases of indigenous polio for almost 2 years.
The Western Pacific Region of WHO was certified as polio-free in October
[2000], becoming the second region after the Americas, which was declared
polio free in 1994. The virus detected in the Dominican Republic was first
isolated by the PAHO Poliovirus Laboratory at the Caribbean Epidemiology
Center and subsequently characterized at the Poliovirus Laboratory at the
CDC. It is unusual because it is derived from OPV, has 97% genetic
similarity to the parental OPV strain (normally OPV derived viruses have
greater than 99.5% similarity), and appears to have assumed the
characteristics of wild poliovirus type 1, both in terms of neurovirulence
and transmissibility. The difference in nucleotide sequence suggests the
virus has either been replicating for a prolonged period in an
immunodeficient individual, or circulating for as long as 2 years in an
area where vaccination coverage is very low, resulting in ongoing genetic
changes in the original Sabin virus that gave it the properties of wild
poliovirus, according to CDC experts.
Prolonged circulation of OPV-derived polioviruses in areas with very low
OPV coverage has been documented in only one other setting. Type 2
OPV-derived virus circulated in Egypt for an estimated 10 years (1983-1993)
and was associated with more than 30 reported cases. In this instance,
vaccination coverage was very low in the affected areas, and circulation of
a vaccine-derived poliovirus was terminated rapidly once OPV vaccination
coverage increased.
"The current outbreak is a powerful reminder that even polio-free areas
need to maintain high coverage with polio vaccine until polio eradication
has been achieved," Dr. de Quadros said. "Nearly 4 decades of experience
with OPV has shown that it is very safe and effective in preventing
poliomyelitis. OPV is the vaccine of choice for the eradication of wild
polioviruses. However, it is crucial to maintain high OPV coverage to
protect against imported wild polioviruses and to prevent person-to-person
transmission of OPV-derived viruses," he added. "It is also important that
all countries maintain high quality AFP [acute flaccid paralysis] and
poliovirus surveillance, that current activities to complete the global
eradication of wild polioviruses be accelerated, and that a global strategy
is developed for the orderly cessation of immunization with OPV after
global certification of polio eradication is achieved," Dr. de Quadros said.
Travelers to the Dominican Republic and Haiti who are not adequately
immunized must be considered at risk of acquiring poliomyelitis, and should
make certain they are fully immunized against polio. Those countries using
OPV for routine immunization recommend at least a 3-dose primary
vaccination series.
