Question

From recent outbreaks (minimum 3), find out how the information about the outbreak and the risk, protection, and other important public health information was disseminated to the public. Include: How long did it take to get out to the public? What media did the public health service and/or WHO use to disseminate? What was the public reaction?

Answer 1

From recent outbreaks (minimum 3), find out how the information about the outbreak and the risk, protection, and other important public health information was disseminated to the public. Include: How long did it take to get out to the public? What media did the public health service and/or WHO use to disseminate? What was the public reaction?

Ans:  There are many outbreak disease in the global world and also the current situation for COVID19 but we have the least amount of information. So, I will describe Four outbreaks which are described below.

1. Measles

Mexico is experiencing a measles outbreak. Between 1 January and 2 April 2020, 1,364 probable1cases of measles were reported, of which 124 were laboratory confirmed, 991 were discarded and 328 remain under investigation. The age of the confirmed measles cases ranged from three months to 68 years (median=20 years), and 59% were male. Analysis conducted by the National Reference Laboratory (InDRE) identified the genotype D8 (similar to other countries in the Region), linage MVs/GirSomnath.IND/42.16/ for 17 of the confirmed cases.

Of the 124 confirmed cases, 105 were in Mexico City, 18 in Mexico State, and one in Campeche State; the following is a summary of the epidemiological situation in each:

In Mexico City, 427 probable cases were reported, of which 105 were laboratory confirmed and 83 remain under investigation. Confirmed cases have been reported in 14 town halls including Gustavo A. Madero (53 cases), Miguel Hidalgo (14 cases), Iztapalapa (9 cases), Cuajimalpa de Morelos (8 cases), Alvaro Obregon (7 cases), Xochimilco (4 cases), Cuauhtémoc (2 cases), Tlahuac (2 cases), Tlalpan (2 cases), Coyoacán (1 case), Azcapotzalco (1 case), Milpa Alta (1 case), and Venustiano Carranza (1 case). All 105 confirmed cases in Mexico City were Mexican citizens, and 60% were male. The highest proportion of confirmed cases were aged between 20 to 29 years (28%), followed by 2 to 9-year-old (17%), 30 to 39-year-old (14%), one-year-old (11%), infants aged less than 12 months (11%), 10 to 19-year-old (10%), and 40 years or above (9%). Of the confirmed cases, only 15 (14%) had a proven2 history of vaccination. Under vaccination may be linked with missed opportunities for vaccination, a lack of access to vaccination services, scheduling limitations impacting parent’s abilities to take their children to get vaccinated, or lack of vaccine stocks. The most recent confirmed case had rash onset on 2 April 2020 and was reported in the Gustavo A. Madero town hall.

In Mexico State, 162 probable cases were reported, of which 18 were laboratory confirmed and 65 remain under investigation. Confirmed cases were reported in eight municipalities of Mexico State including Tlalnepantla (5 cases), Ecatepec de Morelos (4 cases), Nezahualcóyotl (2 cases), Tecámac (2 cases), Toluca (2 cases), Atizapán de Zaragoza (1 case), Chimalhuacán (1 case), Naucalpan (1 case). These 18 confirmed cases were all Mexican citizens, and 56% were male. The highest proportion of confirmed cases was reported among 20 to 29-year-old (22%), followed by 1-year-old (17%), 2 to 9-year-old (17%), 30 to 39-year-old (17%), infants aged less than 12 months (11%), 10 to 19-year-old (11%) and 40-year-old or above (5%). Of the confirmed cases, three cases (33%) had proven history of vaccination. The most recent confirmed case in the State of Mexico had rash onset on 27 March and lives in the Tlalnepantla de Baz municipality.

In Campeche State, eight probable cases were reported, of which one was confirmed and seven remains under investigation. The confirmed case is a 5-year-old female resident of Champoton Municipality who had rash onset on 21 March 2020. The case has a proven history of vaccination. The probable place of exposure was Mérida City, Yucatán State.

The rash onset dates of the confirmed cases in Mexico were between 12 February and 2 April 2020. The Figure 1 shows the progression of the outbreak. An exponential increase of confirmed cases could be observed in the coming weeks.

The WHO Region of the Americas was declared free of measles in September 2016. However, Venezuela and Brazil lost their ‘measles-free’ status on 1 July 2018 and 19 February 2019 respectively due to major measles outbreaks between 2018 and 2019. Of 35 Member States, 33 have maintained the ‘measles-free’ status. In 2019, 14 countries in the Region of the Americas reported confirmed cases of measles including Brazil (19,326 cases, including 15 deaths), the United States of America (1,282 cases), Bolivarian Republic of Venezuela (548 cases, including 3 deaths), Colombia (242 cases, including 1 death), Canada (113 cases), Argentina (107 cases), Mexico (20 cases), Chile (11 cases), Costa Rica (10 cases), Uruguay (9 cases), Bahamas (3 cases), Peru (2 cases), Cuba (1 case), and St. Lucia (1 case). Between 1 January and 4 April 2020, seven countries have reported confirmed measles cases including Brazil (2,194 cases, 4 deaths), Mexico (124 cases), Argentina (54 cases, 1 death), the United States of America (12 cases), Uruguay (2 cases), Chile (2 cases), and Canada (1 case).

Public health response

Actions implemented by the Health authorities include:

• Intensified epidemiological surveillance through active and retrospective institutional case finding, contact tracing, and monitoring of contacts;
• Vaccination activities in the field;
• Risk communication through the epidemiological notice;
• Training activities for field staff;
• Strengthening of the laboratory network.

Risk assessment

Measles is a highly contagious viral disease which affects susceptible individuals of all ages and remains one of the leading causes of death among young children globally, despite the availability of safe and effective measles-containing vaccines. The mode of transmission is airborne or via droplets from the nose, mouth, or throat of infected persons. Initial symptoms, which usually appear 10–12 days after infection, include high fever, usually accompanied by one of several of the following: runny nose, bloodshot eyes, cough, and tiny white spots on the inside of the mouth. Several days later, a rash develops, usually starting on the face and upper neck and gradually spreads downwards. A patient is infectious four days before the start of the rash to four days after the appearance of the rash. There is no specific antiviral treatment for measles and most people recover within 2–3 weeks.

Among malnourished children and people with greater susceptibility, measles can also cause serious complications, including blindness, encephalitis, severe diarrhea, ear infection, and pneumonia. Measles can be prevented by immunization. In countries with low vaccination coverage, epidemics typically occur every two to three years and usually last between two and three months, although their duration varies according to population size, crowding, and the population’s immunity status.

Because of ongoing transmission, vaccination strategies and other actions are being implemented to control the outbreak by local and state level authorities in Mexico. There is a high risk of spreading of the virus due to high population density such as Mexico City, in which the high vaccination coverage could allow slow but steady transmission. At the regional level, the potential impact is considered moderate given the performance of routine immunization programs and prevention and control capacities in other countries in the region and the restrictions for travel in many countries and territories of the Region due to the pandemic of COVID-19.

WHO advice

Since 1 September 2017, the Pan American Health Organization WHO Regional Office of the Americas (PAHO/WHO) has been sharing information on these outbreaks with its Member States and has alerted of the risk of outbreaks occurring from imported measles cases, as well as of the possibility of re-introduction of the disease in areas with low vaccination coverage. In light of continuous reports of imported measles cases from other Regions and ongoing outbreaks in the Americas, PAHO / WHO urges all Member States to follow the new recommendations on the Guidance for Immunization in the context of the COVID-19 settings.

Among the recommendations for countries with measles outbreaks, the following are highlighted:

Vaccination

• Involve the National Immunizations Technical Advisory Group (NITAG) in decision-making on the continuity of vaccination services.
• Under circumstances of vaccine-preventable disease (VPD) outbreak, the decision to conduct outbreak response mass vaccination campaigns will require a risk-benefit assessment on a case by case basis and must factor in the health system’s capacity to effectively conduct a safe and high-quality mass campaign in the context of the COVID-19 pandemic. The assessment should evaluate the risks of a delayed response against the risks associated with an immediate response, both in terms of morbidity and mortality for the VPD and the potential impact of further transmission of the SARS-CoV-2 virus.
• Immunization services should be resumed when the risk of transmission of SARS-CoV-2 has been reduced and the capacity of the health system has recovered sufficiently to resume these activities. It is likely that some level of SARS-CoV-2 transmission will still be in progress when services resume. Strict infection prevention and control measures and social distancing practices are likely to continue in the early stages of resuming the vaccination service. NITAG should advise the country on how to resume service and which populations should be prioritized.
• Vaccinate at-risk populations residing in areas where the measles virus is circulating that do not have proof of vaccination or immunity against measles and rubella, such as health personnel, people working in essential services companies, institutions with a captive population and transportation (hospitals, airports, jails, hostels, border crossings, urban mass transportation and others), as well as international travelers.
• Vaccinate at-risk populations (without proof of vaccination or immunity against measles and rubella), such as healthcare workers, persons working in tourism and transportation (hotels, airports, border crossings, mass urban transportation, and others), and international travelers.
• Maintain a vaccine stock of the measles-rubella (MR) and/or MMR vaccine and syringes/supplies for prevention and control actions of imported cases.

People at High Risk for Complications

People at high risk for severe illness and complications from measles include:

• Infants and children aged <5 years
• Adults aged >20 years
• Pregnant women
• People with compromised immune systems, such as from leukemia and HIV infection

Transmission

Measles is one of the most contagious of all infectious diseases; up to 9 out of 10 susceptible persons with close contact to a measles patient will develop measles. The virus is transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. Measles virus can remain infectious in the air for up to two hours after an infected person leaves an area.

Treatment

There is no specific antiviral therapy for measles. Medical care is supportive and to help relieve symptoms and address complications such as bacterial infections.

Severe measles cases among children, such as those who are hospitalized, should be treated with vitamin A. Vitamin A should be administered immediately on diagnosis and repeated the next day. The recommended age-specific daily doses are

• 50,000 IU for infants younger than 6 months of age
• 100,000 IU for infants 6–11 months of age
• 200,000 IU for children 12 months of age and older

Epidemiological surveillance

• Surveillance systems must continue to carry out early detection and the management of VPD cases, at a minimum for diseases with global surveillance mandates and elimination objectives such as measles and rubella, among others.
• During an outbreak and when it is not possible to confirm the suspected cases by laboratory, classifications of a confirmed case may be based on clinical criteria (fever, rash, cough, coryza and conjunctivitis) and epidemiological link, in order to not delay the response actions.
• Routine surveillance for other VPD should continue as long as possible; when laboratory testing is not possible, samples should be stored appropriately for confirmation when laboratory capacity permits testing. Countries should ensure sufficient sample storage capacity at the provincial and central levels and this should be monitored regularly.
• Strengthen epidemiological surveillance in border areas to rapidly detect and respond to highly suspected cases of measles.

Rapid response

• Provide a rapid response to imported measles cases to avoid the re-establishment of endemic transmission, through the activation of rapid response teams trained for this purpose, and by implementing national rapid response protocols when there are imported cases. Once a rapid response team has been activated, continued coordination between the national and local levels must be ensured, with permanent and fluid communication channels between all levels (national, sub-national, and local).
• During outbreaks, establish adequate hospital case management to avoid nosocomial transmission, with appropriate referral of patients to isolation rooms (for any level of care) and avoiding

2. Ebola virus

From 15 to 21 April 2020, three new confirmed cases of Ebola virus disease (EVD) were reported in the Democratic Republic of the Congo, all from Beni Health Zone in North Kivu Province (Figure 1). Two out of three cases were registered as contacts, though none were regularly followed by the response team because of insecurity and ongoing challenges with community reticence.

In total, six cases have been reported since 10 April, four of whom have passed away; two in the community and two in an Ebola treatment centre (ETC). Currently, there is one confirmed case receiving care at an ETC and one who remains in the community; response teams are engaging with the community in order to try to bring the person to the ETC for access to treatment and supportive care, and to prevent further transmission in the community.

Prior to the emergence of this cluster in Beni, the last person confirmed to have EVD tested negative twice and was discharged from a treatment centre on 3 March 2020. As of 21 April, a total of 762 contacts of these cases have been registered, of which 603 (79%) were followed.

Specimens from all six confirmed cases were sent to the Institut Research Biomédicale (INRB) for genetic sequencing to support surveillance teams in investigating the source of infection and to determine if cases were linked to a known chain of transmission. Laboratory sequencing of the virus showed a link to cases that were confirmed in July 2019, suggesting exposure to a persistent source of infection. Therefore, individuals in the current cluster may have been infected by direct contact with body fluids of a survivor (asymptomatic or relapse case). Investigations into the transmission chains from July 2019 in Beni and Katwa Health Zones, as well as confirmed cases reported in April 2020 are ongoing.

From 15 to 21 April 2020, an average of 2037 alerts were reported and investigated per day. Of these, an average of 196 alerts were validated as suspected cases each day, requiring specialized care and laboratory testing to rule-out EVD. Though the alert rate increased slightly in the past week, it remains at a suboptimal level as teams are pulled into other emergencies, including COVID-19. Response teams also face other challenges, such as the presence of armed groups and limited access to some communities.

Timely testing of suspected cases continues to be provided from nine laboratories. From 13 to 19 April 2020, 1030 samples were tested including 583 blood samples from alive, suspected cases; 267 swabs from community deaths; and 180 samples from re-tested patients. Overall, laboratory activities increased by 6% compared to the previous week.

As of 21 April 2020, a total of 3461 EVD cases, including 3316 confirmed and 145 probable cases have been reported, of which 2279 cases died (overall case fatality ratio 66%). Of the total confirmed and probable cases, 56% (n=1943) were female, 28% (n=983) were children aged less than 18 years, and 5% (n=171) were health care workers. As of 21 April, a total of 1169 cases have recovered from EVD.

An urgent injection of US $20 million is required to ensure that response teams have the capacity to maintain the appropriate level of operations through to the beginning of May 2020.

Public health response

For further information about public health response actions by the Ministry of Health, WHO, and partners, please refer to the latest situation reports published by the WHO Regional Office for Africa:

• Ebola situation reports: Democratic Republic of the Congo

Risk assessment

On 14 April 2020, WHO revised the risk assessment for this event from High to Moderate at the national and regional levels, while the risk level remained Low at the global level. The risk assessment will be continuously reassessed in the coming days based on available and shared information.

For further information, please see the Statement on the meeting of the International Health Regulations (2005) Emergency Committee for Ebola virus disease in the Democratic Republic of the Congo on 14 April 2020

WHO advice

WHO advises against any restriction of travel to, and trade with, the Democratic Republic of the Congo based on the currently available information regarding this EVD outbreak. Any requirements for certificates of Ebola vaccination are not a reasonable basis for restricting movement across borders or the issuance of visas for travellers to/from the affected countries. WHO continues to closely monitor and, if necessary, verify travel and trade measures in relation to this event. Currently, no country has implemented travel measures that significantly interfere with international traffic to and from the Democratic Republic of the Congo in relation to this EVD outbreak. Travellers should seek medical advice before travel and should practise good hygiene. Further information is available in the WHO recommendations for international traffic related to the Ebola Virus Disease outbreak in the Democratic Republic of the Congo.

Prevention:

When living in or traveling to a region where Ebola virus is present, there are a number of ways to protect yourself and prevent the spread of EVD

• Contact with blood and body fluids (such as urine, feces, saliva, sweat, vomit, breast milk, semen, and vaginal fluids) of persons who are ill.
• Contact with semen from a man who has recovered from EVD, until testing verifies the virus is gone from the semen.
• Items that may have come in contact with an infected person’s blood or body fluids (such as clothes, bedding, needles, and medical equipment).
• Funeral or burial rituals that require handling the body of someone who died from EVD.
• Contact with bats and nonhuman primates’ blood, fluids, or raw meat prepared from these animals (bushmeat).
• Contact with the raw meat of an unknown source.

Ebola Vaccine

The U.S. Food and Drug Administration (FDA) approved the Ebola vaccine rVSV-ZEBOV (tradename “Ervebo”) on December 19, 2019. The rVSV-ZEBOV vaccine is a single dose vaccine regimen that has been found to be safe and protective against only the Zaire ebolav

Treatment

Symptoms of Ebola virus disease (EVD) are treated as they appear. When used early, basic interventions can significantly improve the chances of survival. These include:

• Providing fluids and electrolytes (body salts) through infusion into the vein (intravenously).
• Offering oxygen therapy to maintain oxygen status.
• Using medication to support blood pressure, reduce vomiting and diarrhea and to manage fever and pain.
• Treating other infections, if they occur.

Antiviral Drugs

There is currently no antiviral drug licensed by the U.S. Food and Drug Administration (FDA) to treat EVD in people.

During the 2018 eastern Democratic Republic of the Congo outbreak, four investigational treatments were initially available to treat patients with confirmed Ebola. For two of those treatments, called regeneron (REGN-EB3) and mAb114, overall survival was much higher. These two antiviral drugs currently remain in use for patients with confirmed Ebola.

3. Yellow fever

On 3 March 2020, the Ethiopian Public Health Institute (EPHI) reported three suspected yellow fever cases in Enor Ener Woreda, Gurage zone, SNNPR. The three reported cases were members of the same household (father, mother and son) located in a rural kebele. Two of three samples tested positive at national level by reverse transcriptase-polymerase chain reaction (RT-PCR) and were subsequently confirmed positive by plaque reduction neutralization testing (PRNT) at the regional reference laboratory, Uganda Viral Research Institute (UVRI) on 28 March 2020.

In response to the positive RT-PCR results, the EPHI and Ministry of Health performed an in-depth investigation and response, supported by partners including WHO.

As of 6 April 2020, a total of 85 suspected cases have been notified from 6 kebeles in Enor Ener Woreda, of which 54 were reported from Wedesha kebele. Among the total suspected cases, 6 samples tested positive at EPHI national laboratory and they have been referred to UVRI for confirmation.

Public health response

• Epidemiological and entomological investigation has been conducted in Enor Ener Woreda since 8 March 2020.
• Rapid activation of vaccination response has been put in place. The country has rapidly mounted a reactive campaign from 26 to 31 March 2020 targeting approximately 32,000 persons in the affected and surrounding kebeles (12 kebeles total).
• An International Coordination Group (ICG) request is in process by the country for a larger scale reactive campaign.

Risk assessment

The risk at national level is assessed as high. The current outbreak in Gurage Zone, SNNP region shows rapid amplification of a yellow fever outbreak in a rural area. In the context of virtually no population immunity, the high number of suspect cases reported over a short time period is of high concern. The recent confirmation of the outbreak in cases with no history of travel is a concern. This is an indication of the existence of conducive factors for an increased incidence of yellow fever transmission and the spread of the disease beyond the hotspot areas.

Recent entomological studies, in addition to previous entomological studies conducted in 2018, have indicated the presence of competent vectors including Aedes species and the potential for spread to surrounding zones. The onset of the rainy season could increase density of mosquito vectors, thereby further exacerbating risk of spread.

Travellers returning to Ethiopia who may be infected with possible high levels of the virus in the blood may pose a risk for the establishment of local cycles of yellow fever transmission in areas where the competent vector is present.

The last yellow fever outbreak occurred in the SNNP region in August 2018, with a total of 35 cases (30 suspected and 5 confirmed cases) reported from the Wolayita Zone in the SNNP region, Ethiopia. While immunization took place in selected aspects of Wolayita Zone, the communities in Gurage zone remain vulnerable to yellow fever infection.

WHO advice

Ethiopia is a high priority country for the Eliminate Yellow Fever Epidemic (EYE) strategy. Introduction of yellow fever vaccination into routine immunization is planned for 2020. Vaccination is the primary means for prevention and control of yellow fever. In urban centres, targeted vector control measures are also helpful to interrupt transmission. WHO and partners will continue to support local authorities to implement these interventions to control the current outbreak.

WHO recommends vaccination against yellow fever for all international travellers 9 months of age or older going to Ethiopia. Ethiopia also requires a yellow fever vaccination certificate for travellers aged 9 months or older arriving from countries with risk of yellow fever transmission and for travellers having transited for more than 12 hours through an airport of a country with risk of yellow fever transmission. WHO does not generally recommend vaccination for travellers whose itineraries are limited to Afar and Somali provinces.

Yellow fever vaccination is safe, highly effective and provides life-long protection. In accordance with the International Health Regulations (2005), third edition, the validity of the international certificate of vaccination against yellow fever extends to the life of the person vaccinated. A booster dose of yellow fever vaccine cannot be required of international travellers as a condition of entry.

WHO encourage its Member States to take all actions necessary to keep travellers well informed of risks and preventive measures including vaccination. Travellers should also be made aware of yellow fever symptoms and signs and instructed to rapidly seek medical advice if experiencing signs and symptoms suggestive of yellow fever infection.

Prevention of Yellow Fever

The most effective way to prevent infection from Yellow Fever virus is to prevent mosquito bites. Mosquitoes bite during the day and night. Use insect repellent, wear long-sleeved shirts and pants, treat clothing and gear, and get vaccinated before traveling, if vaccination is recommended for you.

Prevent Mosquito Bites

Use Insect Repellent

Use Environmental Protection Agency (EPA)-registered insect repellentsexternal icon with one of the active ingredients below. When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breastfeeding women.

• DEET
• Picaridin (known as KBR 3023 and icaridin outside the US)
• IR3535
• Oil of lemon eucalyptus (OLE)
• Para-menthane-diol (PMD)
• 2-undecanone

Find the right insect repellent for you by using EPA’s search toolexternal icon.

Tips for babies and children

• Dress your child in clothing that covers arms and legs.
• Cover strollers and baby carriers with mosquito netting.
• When using insect repellent on your child:

• Always follow label instructions.
• Do not use products containing oil of lemon eucalyptus (OLE) or para-menthane-diol (PMD) on children under 3 years old.
• Do not apply insect repellent to a child’s hands, eyes, mouth, cuts, or irritated skin.
  • Adults: Spray insect repellent onto your hands and then apply to a child’s face.

Tips for Everyone

• Always follow the product label instructions.
• Reapply insect repellent as directed.

• Do not spray repellent on the skin under clothing.
• If you are also using sunscreen, apply sunscreen first and insect repellent second.

Natural insect repellents (repellents not registered with EPA)

• We do not know the effectiveness of non-EPA registered insect repellents, including some natural repellents.
• To protect yourself against diseases spread by mosquitoes, CDC and EPA recommend using an EPA-registered insect repellent.
• Choosing an EPA-registered repellent ensures the EPA has evaluated the product for effectiveness.
• Visit the EPA website to learn more.external icon

Wear long-sleeved shirts and long pants

Treat clothing and gear

• Use permethrin to treat clothing and gear (such as boots, pants, socks, and tents) or buy permethrin-treated clothing and gear.

• Permethrin is an insecticide that kills or repels mosquitoes.
• Permethrin-treated clothing provides protection after multiple washings.
• Read product information to find out how long the protection will last.
• If treating items yourself, follow the product instructions.
• Do not use permethrin products directly on skin.

Take steps to control mosquitoes indoors and outdoors

• Use screens on windows and doors. Repair holes in screens to keep mosquitoes outdoors.
• Use air conditioning, if available.
• Stop mosquitoes from laying eggs in or near water.

• Once a week, empty and scrub, turn over, cover, or throw out items that hold water, such as tires, buckets, planters, toys, pools, birdbaths, flowerpots, or trash containers.
• Check indoors and outdoors.

Prevent mosquito bites when traveling overseas

• Choose a hotel or lodging with air conditioning or screens on windows and doors.
• Sleep under a mosquito bed net if you are outside or in a room that does not have screens.

• Buy a bed net at your local outdoor store or online before traveling overseas.
• Choose a WHOPES-approved bed net: compact, white, rectangular, with 156 holes per square inch, and long enough to tuck under the mattress.
• Permethrin-treated bed nets provide more protection than untreated nets.
  • Do not wash bed nets or expose them to sunlight. This will break down the insecticide more quickly.
  • For more information on bed nets, visit CDC’s page on insecticide-treated bed nets.
  • For more information on traveling overseas, visit Travelers’ Health.

4. Dengue fever

Through event-based surveillance performed throughout 2019, WHO became aware of a dengue outbreak in Mayotte, France, since July 2019. According to the local health authority (Agence Régionale de Santé) of Mayotte, dengue cases were reported since March 2019; however, the epidemic intensified during January 2020 when the number of cases increased significantly.

From the beginning of January 2020 to 17 April 2020, 3533 confirmed cases of dengue fever have been reported on the island, including 16 deaths. Of the 3533 cases, 339 were hospitalized and 21 cases were managed in intensive care units. From 23 February 2020 to 21 March 2020, six out of 17 communes in Mayotte had an incidence rate of more than 5%.

The vast majority of the dengue cases in this outbreak have been caused by dengue virus serotype 1 (DENV-1).

In the past, Mayotte has reported four dengue outbreaks, in 1993, 2010 (caused by DENV-3), and in 2013 and 2014 (caused by DENV-2), which were recorded in several communes of the main island of Mayotte and the small island of Petite-Terre. The current outbreak is the largest outbreak of dengue in Mayotte reported to date. Prior to this, the largest outbreak was recorded in 2014 with 522 laboratory confirmed cases, of which 494 cases were confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) and 27 were confirmed by serologic tests. During the 2014 outbreak, only serotype DENV-2 was identified.

Public health response

Health authorities in Mayotte have implemented the following measures:

• Strengthening integrated vector control activities;
• Enhancing surveillance to identify cases;
• Updating clinical management guidelines, social mobilization and emergency risk communications.

Risk assessment

Mayotte Island is part of the Comoros archipelago (Mozambique Channel, southwestern Indian Ocean), which is under French administration. Since 2019, only circulation of DENV-1 has been established in Mayotte. However, epidemics caused by other serotypes are currently underway in the Indian Ocean area, making it possible for another serotype to be introduced to Mayotte. A shift in the predominant DENV serotype may result in more severe secondary dengue virus infections and severe dengue cases requiring hospitalization and good case management. A comprehensive risk communication should be developed.

Due to the presence and sufficient density of the competent vectors (Aedes albopictus and Aedes aegypti), hot and humid climate, and the current rainy season (tropical maritime climate with a hot rainy season from November to May), further upsurge in cases cannot be ruled out.

Mayotte only has one hospital and 16 beds in the intensive care unit, and recourse to traditional medicine is also frequent. Additionally, underreporting of dengue cases cannot be excluded.

WHO advice

There is no specific treatment for dengue. However, timely detection of cases, identifying any warning signs of severe cases of dengue, and appropriate early case management are key elements of care to prevent deaths due to dengue. A delay in seeking medical care in severe dengue cases is often related to deaths from dengue virus disease. Outer islands should refer cases or seek help as early as possible.

Additionally, Integrated Vector Management (IVM) activities should be enhanced to remove potential breeding sites, reduce vector populations, and minimize individual exposure. This should include both larval and adult vector control strategies (i.e. environmental management and source reduction and chemical control measures). Vector control measures should be implemented at households, places of work, schools, and healthcare facilities, among others, to prevent vector-person contact.

Given that Aedes mosquitoes, the competent vector, has greater activity during the day, personal protection measures are recommended, such as wearing protective clothing that minimizes skin exposure and using repellents that can be applied to exposed skin or clothes strictly as instructed on the label. Window and door screens, and mosquito nets (impregnated or not with insecticide) can be useful to reduce vector-person contact in closed spaces during the day or night.

Prevention

• Prevent dengue by avoiding mosquito bites.
• All four dengue viruses are spread primarily through the bite of an infected Aedes species (Ae. aegypti and Ae. albopictus) mosquito. These mosquitoes also spread chikungunya and Zika viruses.
• The mosquitoes that spread dengue are found in most tropical and subtropical regions of the world, including many parts of the United States.
• Ae. aegypti and Ae. albopictus bite during the day and night.
• A dengue vaccine is available for use in some parts of the world, including United States territories.

Use the Tips Below to Protect Yourself and Others from Dengue

• Following these tips will help to protect you, your partner, your family, your friends, and your community from dengue.
• The more steps you take, the more protected you are.

Prevent Mosquito Bites

• Dengue is spread to people through the bite of an infected mosquito.
• Mosquitoes that spread dengue virus bite during the day and night. These types of mosquitoes also spread chikungunya and Zika viruses.
• The best way to prevent these diseases is to protect yourself from mosquito bites.
• Find an insect repellent right for you by using EPA’s search toolexternal icon.

What you can do

• Traveling? Visit CDC’s country-specific travel recommendations.
• Take steps to prevent mosquito bites.
• Take steps to control mosquitoes inside and outside your home.

If You Have Dengue, Protect Others

• During the first week of infection, dengue virus is found in the blood of an infected person. If a mosquito bites the infected person, the mosquito becomes infected. The infected mosquito can spread the virus to other people through bites.
• Not everyone infected with dengue gets sick. Even if you do not feel sick, travelers returning to the United States from an area with risk of dengue should take steps to prevent mosquito bites for 3 weeks so they do not spread dengue to mosquitoes that could spread the virus to other people.