Surveillance for acute flaccid paralysis (AFP) in Madagascar has
detected a cluster of four cases of paralytic poliomyelitis from which
type-2 vaccine-derived polioviruses have been isolated. Preliminary
data indicate that these patients, residing in the Tolagnaro district
of Toliara province in southeastern Madagascar, had onset of paralysis
during March 20--April 12, 2002. None of the children affected was
vaccinated fully. During March--April 2002, provincial authorities
conducted a small-scale house-to-house vaccination response. Genetic
sequencing studies of these vaccine-derived viruses indicate
substantial genetic drift and recombination with nonpolio
enteroviruses. These findings are compatible with an outbreak of
paralytic polio associated with a circulating vaccine-derived
poliovirus (cVDPV); however, further investigation is required.
The three outbreaks of cVDPV described previously occurred in areas
where routine oral polio vaccine (OPV) coverage is low, AFP
surveillance is suboptimal, and supplementary vaccination activities
have not been conducted for years [1,2].
Vaccination coverage data suggest that during 1999, 37% of children
aged <1 year had received 3 doses of OPV. In 2001, the nonpolio AFP
rate of 0.3 case per 100,000 population aged <15 years was below the
target level of 1.0.
A joint mission by the Ministry of Health of Madagascar, the
Pasteur Institute of Madagascar, the World Health Organization, and
United Nations Children's Fund (UNICEF) is ongoing to 1) conduct a
field investigation of the cases to verify early reports, 2) review
health facility records for any missed cases, 3) enhance the quality
of AFP surveillance nationwide, and 4) plan for a nationwide
house-to-house polio vaccination response. The work of this mission is
being complemented by laboratory work in Madagascar, South Africa,
France, and the United States.
Reported by: Ministry of Health; Pasteur Institute,
Madagascar. National Institute for Communicable Diseases, South
Africa. Pasteur Institute, Paris, France. World Health Organization
Regional Office for Africa, Harare, Zimbabwe. Vaccines and Biologicals
Dept, World Health Organization, Geneva, Switzerland. Div of Viral and
Rickettsial Diseases, National Center for Infectious Diseases; Global
Immunization Div, National Immunization Program, CDC.
