YELLOW FEVER DISEASE

 

YELLOW FEVER VIRUS

 

The yellow fever virus is found in tropical and subtropical areas of Africa and South America. The virus is spread to people by the bite of an infected mosquito. Illness ranges from a fever with aches and pains to severe liver disease with bleeding and yellowing skin (jaundice). Yellow fever infection is diagnosed based on laboratory testing, a person’s symptoms, and travel history. There is no medicine to treat or cure infection. To prevent getting sick from yellow fever, use insect repellent, wear long-sleeved shirts and long pants, and get vaccinated.Fall under the family flaviviridae,It is enveloped virus with an icosahedral capsid,Single stranded linear non segmented RNA.The envelope has three structural polypeptides, two are glycosylated.Yellow fever virus multiplies in many different types of animals and in mosquitoes

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Mode transmission of yellow fever

Yellow fever virus is an RNA virus that belongs to the genus Flavivirus. It is related to West Nile, St. Louis encephalitis, and Japanese encephalitis viruses. Yellow fever virus is transmitted to people primarily through the bite of infected Aedes or Haemagogus  species  both are mosquitoes. These mosquitoes acquire the virus after feeding on infected human or non-human and then can transmit the virus to other human or non-human. People infected with yellow fever virus are infectious to mosquitoes (referred to as being “viremic”) shortly before the onset of fever and up to 5 days after onset.

 

 

Yellow fever virus has three transmission cycles: jungle (sylvatic), inter­mediate (savannah), and urban.

• The jungle (sylvatic) cycle involves transmission of the virus between non-human primates (e.g., monkeys) and mosquito species found in the forest canopy. The virus is transmitted by mosquitoes from monkeys to humans when humans are visiting or working in the jungle.
• In Africa, an intermediate (savannah) cycle exists that involves transmission of virus from mosquitoes to humans living or working in jungle border areas. In this cycle, the virus can be transmitted from monkey to human or from human to human via mosquitoes.
• The urban cycle involves trans­mission of the virus between humans and urban mosquitoes, primarily Aedes aegypti. The virus is usually brought to the urban setting by a viremic human who was infected in the jungle or savannah.

 

 

 

What are the disease Caused by Yellow Fever Virus?

·         Yellow fever virus  can cause different diseases examples acute, febrile, mosquito-borne illness characterized by liver and renal,Dysfunction and hemorrhage

 

Symptoms, Diagnosis, & Treatment

The majority of people infected with yellow fever virus will either not have symptoms, or have mild symptoms and completely recover.For people who develop symptoms, the time from infection until illness is typically 3 to 6 days.

Because there is a risk of severe disease, all people who develop symptoms of yellow fever after traveling to or living in an area at risk for the virus should see their healthcare provider near them or for traveler who will be entered in different port of entry should be checked if they have symptoms and have get the vaccine. Once you have been infected, you are likely to be protected from future infections.

 

What are the Symptoms of yellow fever virus?

According to research observation most people will not have any symptoms at all.But Some people will develop yellow fever illness with initial symptoms including:

• Sudden onset of fever
• Chills
• Severe headache
• Back pain
• General body aches
• Nausea
• Vomiting
• Fatigue (feeling tired)
• Weakness

Most people with the initial symptoms improve within one week.For some people who recover, weakness and fatigue (feeling tired) might last several months.A few people will develop a more severe form of the disease.For 1 out of 7 people who have the initial symptoms, there will be a brief remission (a time you feel better) that may last only a few hours or for a day, followed by a more severe form of the disease.

 

Severe symptoms of yellow fever include:

• High fever
• Yellow skin (jaundice)
• Bleeding
• Shock
• Organ failure

Severe yellow fever disease can be deadly. If you develop any of these symptoms, see a healthcare provider immediately.Among those who develop severe disease, 30-60% die.

 

Diagnosis of yellow fever virus

• Yellow fever infection is diagnosed based on laboratory testing, a person’s symptoms, and travel history.

• There is no medicine to treat or cure infection from yellow fever.
• Rest, drink fluids, and use pain relievers and medication to reduce fever and relieve aching.
• Avoid certain medications, such as aspirin or other nonsteroidal anti-inflammatory drugs, for example ibuprofen (Advil, Motrin), or naproxen (Aleve), which may increase the risk of bleeding.
• People with severe symptoms of yellow fever infection should be hospitalized for close observation and supportive care.
• If after returning from travel you have symptoms of yellow fever (usually about a week after being bitten by an infected mosquito), protect yourself from mosquito bites for up to 5 days after symptoms begin. This will help prevent spreading yellow fever to uninfected mosquitoes that can spread the virus to other people.

 

Prevention of Yellow Fever disease

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

 

Tips for babies and children to prevent them from yellow fever

• 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 to prevent from yellow fever disease

• 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.

 

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.

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Laboratory Diagnosis of yellow fever

Yellow fever virus can be diagnostic in the hospital by using human Specimen Blood and Biopsy by using serological technique.

Areas with Risk of Yellow Fever Virus Transmission in Africa¹

Map is current as of August 2018. This map is an updated version of the 2010 map created by the Informal WHO Working Group on the Geographic Risk of Yellow Fever.

 Yellow fever (YF) vaccination is generally not recommended in areas where there is low potential for YF virus exposure. However, vaccination might be considered for a small subset of travelers to these areas who are at increased risk for exposure to YF virus because of prolonged travel, heavy exposure to mosquitoes, or inability to avoid mosquito bites. Consideration for vaccination of any traveler must take into account the traveler’s risk of being infected with YF virus, country entry requirements, and individual risk factors for serious vaccine-associated adverse events (e.g., age, immune

Data Table: Countries with risk of yellow fever virus (YFV) transmission³

·         Angola

·         Benin

·         Burkina Faso

·         Burundi

·         Cameroon

·         Central African Republic

·         Chad⁴

·         Congo, Republic of the

·         Côte d’Ivoire

·         Democratic Republic of the Congo

·         Equatorial Guinea

·         Ethiopia⁴

·         Gabon

·         The Gambia

·         Ghana

·         Guinea

·         Guinea-Bissau

·         Kenya⁴

·         Liberia

·         Mali⁴

·         Mauritania⁴

·         Niger⁴

·         Nigeria

·         Senegal

·         Sierra Leone

·         South Sudan

·         Sudan⁴

·         Togo

·         Uganda

Countries/areas where “a risk of yellow fever transmission is present,” as defined by the World Health Organization, are countries or areas where “yellow fever has been reported currently or in the past, plus vectors and animal reservoirs currently exist”.

These countries are not holoendemic (only a portion of the country has risk of yellow fever transmission).

Countries with low potential for exposure to yellow fever virus (YFV)⁵

·         Eritrea⁶

·         Rwanda

·         São Tomé⁶

·         Somalia⁶

·         Tanzania

·         Zambia⁶

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⁵Countries listed in this table are not contained on the official WHO list of countries with risk of YFV transmission. Therefore, proof of yellow fever vaccination should not be required if traveling from one of these countries to another country with a vaccination entry requirement (unless that country requires proof of yellow fever vaccination from all arriving travelers).

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