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WEEKLY BULLETIN ON OUTBREAKS
AND OTHER EMERGENCIES
Week 21: 16 – 22 May 2022
Data as reported by: 17:00; 22 May 2022
...
Dengue fever São Tomé and Príncipe
103 cases
0 Death
EVENT DESCRIPTION
The Minister of Health of São Tomé and Príncipe (STP) officially
declared an outbreak of dengue fever on 4 May 2022, becoming
the first reported dengue fever outbreak in the country. An alert was
initially notified from the clinical management team at a hospital
in the capital city of São Tomé on 11 April 2022. This was after a
27-year-old male with symptoms suggestive of dengue infection
presented at the facility eight days after arriving from Guadeloupe
Island in the Caribbean which is endemic for dengue. He was tested
but was not confirmed as an acute case of dengue but rather found
positive for IgG antibodies suggesting prior infection within recent
weeks.
Nevertheless, the suspected case triggered the Epidemiological
Surveillance Department to mobilize a multidisciplinary
investigation team in collaboration with the National Endemic
Center to investigate the case, personal contacts, and identify
mosquito vectors and their breeding sites at the case’s home.
From 18 April to 17 May 2022, 103 cases and no deaths have been
confirmed via rapid diagnostic test (RDT) from five health districts
including Água Grande (90, 87.4%); Mézochi (7, 6.8%); Lobata (4,
3.9%); Cantagalo (1, 1.0%); and Autonomous Region of Príncipe
(RAP) (1, 1.0%). The attack rate of Água Grande is by far the largest
at 10.7 cases per 10 000 inhabitants. The most affected age groups
are: 10-19 years (5.9 cases per 10 000), 30-39 years (7.3 cases per
10 000), 40-49 years (5.1 cases per 10 000) and 50-59 years (6.1
cases per 10 000). The most frequent clinical signs are fever (97,
94%), headache (78, 76%) and myalgia (64, 62%).
All cases have been confirmed positive by RDT, however a total
of 30 samples were sent to the Institute of Hygiene and Tropical
Medicine of the New University of Lisbon (IHMT – NOVA) in
Portugal for further testing and were received on 29 April. RDT
SD Bioline Dengue Duo NS1/IgM/IgG combo was used to confirm
the diagnosis of dengue. Results from IHMT-NOVA revealed 20
NS1 positive samples (67% positivity rate), indicating a diagnosis
of acute dengue infection. The 20 NS1 positive samples were
then tested further by real time polymerase chain reaction and
six samples were confirmed positive with dengue virus serotype
3 (DENV-3) as the predominant serotype. Preliminary results also
suggest the possibility of other serotypes present within the batch
of samples.
According to preliminary epidemiological and clinical reports, the
index case was identified as having clinically compatible symptoms
of dengue fever starting 11 April 2022 and had a recent history of
travel to European and Asian countries though was unrelated to the
initially detected case for this outbreak. The index case’s infection
was ultimately deemed to be an autochthonous case and the
possibility of importation has been ruled out. Available information
indicates that this case acquired the disease in São Tomé or in the
RAP.
The country’s rainy season generally lasts 9 months from September
to May, but from December 2021 to early March 2022, the country
experienced torrential rains of great intensity and long duration
causing floods. Rains are expected to continue until June this year
and have already accumulated stagnant water providing favourable
conditions for mosquito breeding sites. Flooding has also caused
issues for waste and sanitation management activities in the
country and therefore conditions are prevalent for transmission
of other potential diseases as well as malnutrition as a result of
damaged agricultural crops causing food insecurity.
PUBLIC HEALTH ACTIONS
Coordination meetings are held weekly by the Ministry of
Health to discuss technical aspects of the outbreak;
A national dengue response plan has been developed, validated
and disseminated;
Epidemiological investigations and active case detections have
been conducted;
Entomological investigations have been carried out to identify
breeding sites and conduct fumigation and source reduction
measures in limited affected localities;
External experts to strengthen laboratory capacity will soon
be deployed to STP, and potentially other experts for case
management, risk communication, and entomology/vector
control.
SITUATION INTERPRETATION
The first officially declared dengue fever outbreak has been reported in STP. The magnitude of the dengue outbreak in the country may be largely underestimated considering the limitations of diagnostic capacity, high asymptomatic rates, limited intensive health care resources, and an untested surveillance system for dengue outbreaks. The ongoing rainy season and recent flooding in the past few months have led to favourable environmental conditions to transmit the disease and has also weakened the country’s sanitation, hygiene, and infrastructural systems which may contribute to more infectious disease and malnutrition due to the loss of agricultural crops by floods. Rains are expected to continue until June this year, and this calls for boosting of preparedness and response measures in the country.
AND OTHER EMERGENCIES
Week 21: 16 – 22 May 2022
Data as reported by: 17:00; 22 May 2022
...
Dengue fever São Tomé and Príncipe
103 cases
0 Death
EVENT DESCRIPTION
The Minister of Health of São Tomé and Príncipe (STP) officially
declared an outbreak of dengue fever on 4 May 2022, becoming
the first reported dengue fever outbreak in the country. An alert was
initially notified from the clinical management team at a hospital
in the capital city of São Tomé on 11 April 2022. This was after a
27-year-old male with symptoms suggestive of dengue infection
presented at the facility eight days after arriving from Guadeloupe
Island in the Caribbean which is endemic for dengue. He was tested
but was not confirmed as an acute case of dengue but rather found
positive for IgG antibodies suggesting prior infection within recent
weeks.
Nevertheless, the suspected case triggered the Epidemiological
Surveillance Department to mobilize a multidisciplinary
investigation team in collaboration with the National Endemic
Center to investigate the case, personal contacts, and identify
mosquito vectors and their breeding sites at the case’s home.
From 18 April to 17 May 2022, 103 cases and no deaths have been
confirmed via rapid diagnostic test (RDT) from five health districts
including Água Grande (90, 87.4%); Mézochi (7, 6.8%); Lobata (4,
3.9%); Cantagalo (1, 1.0%); and Autonomous Region of Príncipe
(RAP) (1, 1.0%). The attack rate of Água Grande is by far the largest
at 10.7 cases per 10 000 inhabitants. The most affected age groups
are: 10-19 years (5.9 cases per 10 000), 30-39 years (7.3 cases per
10 000), 40-49 years (5.1 cases per 10 000) and 50-59 years (6.1
cases per 10 000). The most frequent clinical signs are fever (97,
94%), headache (78, 76%) and myalgia (64, 62%).
All cases have been confirmed positive by RDT, however a total
of 30 samples were sent to the Institute of Hygiene and Tropical
Medicine of the New University of Lisbon (IHMT – NOVA) in
Portugal for further testing and were received on 29 April. RDT
SD Bioline Dengue Duo NS1/IgM/IgG combo was used to confirm
the diagnosis of dengue. Results from IHMT-NOVA revealed 20
NS1 positive samples (67% positivity rate), indicating a diagnosis
of acute dengue infection. The 20 NS1 positive samples were
then tested further by real time polymerase chain reaction and
six samples were confirmed positive with dengue virus serotype
3 (DENV-3) as the predominant serotype. Preliminary results also
suggest the possibility of other serotypes present within the batch
of samples.
According to preliminary epidemiological and clinical reports, the
index case was identified as having clinically compatible symptoms
of dengue fever starting 11 April 2022 and had a recent history of
travel to European and Asian countries though was unrelated to the
initially detected case for this outbreak. The index case’s infection
was ultimately deemed to be an autochthonous case and the
possibility of importation has been ruled out. Available information
indicates that this case acquired the disease in São Tomé or in the
RAP.
The country’s rainy season generally lasts 9 months from September
to May, but from December 2021 to early March 2022, the country
experienced torrential rains of great intensity and long duration
causing floods. Rains are expected to continue until June this year
and have already accumulated stagnant water providing favourable
conditions for mosquito breeding sites. Flooding has also caused
issues for waste and sanitation management activities in the
country and therefore conditions are prevalent for transmission
of other potential diseases as well as malnutrition as a result of
damaged agricultural crops causing food insecurity.
PUBLIC HEALTH ACTIONS
Coordination meetings are held weekly by the Ministry of
Health to discuss technical aspects of the outbreak;
A national dengue response plan has been developed, validated
and disseminated;
Epidemiological investigations and active case detections have
been conducted;
Entomological investigations have been carried out to identify
breeding sites and conduct fumigation and source reduction
measures in limited affected localities;
External experts to strengthen laboratory capacity will soon
be deployed to STP, and potentially other experts for case
management, risk communication, and entomology/vector
control.
SITUATION INTERPRETATION
The first officially declared dengue fever outbreak has been reported in STP. The magnitude of the dengue outbreak in the country may be largely underestimated considering the limitations of diagnostic capacity, high asymptomatic rates, limited intensive health care resources, and an untested surveillance system for dengue outbreaks. The ongoing rainy season and recent flooding in the past few months have led to favourable environmental conditions to transmit the disease and has also weakened the country’s sanitation, hygiene, and infrastructural systems which may contribute to more infectious disease and malnutrition due to the loss of agricultural crops by floods. Rains are expected to continue until June this year, and this calls for boosting of preparedness and response measures in the country.
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