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How do rare mosquito borne diseases get transmitted if they are so rare?

How do rare mosquito borne diseases get transmitted if they are so rare?


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I recently read a somewhat alarmist notice by the state board of health in NH who claimed that some man had tested positive for Jamestown Canyon virus, a rare disease even in its natural environment of Colorado. Supposedly the man has not travelled out of state.

So, I am wondering how it is possible for such a virus to be transmitted. My understanding is that a mosquito only bites twice then it breeds, so basically what has to happen is the first bite has to be on an infected human (or animal) and then the second bite on the victim. So, if this guy got Jamestown Canyon virus, then he must have been in mosquito range of some other infected creature of which we have no knowledge.

Now, unless there is some type of animal that is endemically infected with Jamestown Canyon virus which is transferable to humans, it would seem unlikely to me that there would be any source from which the man could have gotten the virus.

So, I am wondering what kind of plausible scenario would have made this disease transmission possible, assuming it really occurred?


Via Wikipedia:

The virus is transmitted in saliva to a vertebrate host when an infected mosquito takes a blood meal. It thus cycles between mosquito and vertebrate amplifier hosts, mainly white-tailed deer. In a study from Newfoundland, JCV was significantly associated with large mammals such as sheep, cattle and horses. In Michigan and Ontario moose and bison are believed to be the primary reservoir.[3]

The virus winters in mosquito eggs, which it reaches by transovarial transmission. The female mosquito lays eggs that carry the virus, and the offspring can transmit the virus to deer or ruminants and humans. Infected mosquitoes were found equally distributed throughout the state of Connecticut, irrespective of land use.[4]

So, the virus has a reservoir in (primarily) deer, an infected deer gets bitten by a female mosquito, the mosquito lays eggs with the virus, the resulting mosquitoes can spread the disease by biting another large animal or human.

The reservoir needs to be large enough to ensure the virus survives year over year, but there doesn't need to be any special mechanism for it to travel outside the predominant range; there have been cases in several states in the northeast, though rare.


References [3] and [4] are:

[3] Goff G, Whitney H, Drebot MA (2012). "Roles of host species, geographic separation, and isolation in the seroprevalence of Jamestown Canyon and snowshoe hare viruses in Newfoundland". Appl. Environ. Microbiol. 78 (18): 6734-40. doi:10.1128/AEM.01351-12. PMC 3426688. PMID 22798366.

[4] Andreadis TG, Anderson JF, Armstrong PM, Main AJ (2008). "Isolations of Jamestown Canyon virus (Bunyaviridae: Orthobunyavirus) from field-collected mosquitoes (Diptera: Culicidae) in Connecticut, USA: a ten-year analysis, 1997-2006". Vector Borne Zoonotic Dis. 8 (2): 175-88. doi:10.1089/vbz.2007.0169. PMID 18386967.


EEEV is maintained through a natural cycle between the Culiseta melanura mosquitoes and birds. The spread of EEEV to mammals (including humans and horses) occurs through the bite of certain infected mosquito species (i.e. Aedes, Coquillettidia, and Culex) that feed on both birds and mammals. EEE is only spread to humans through the bite of an infected mosquito. EEE is not spread person-to-person, people to animals, or animals to people.

It is possible that some people who are infected with EEEV will not develop any symptoms. Symptoms of EEEV infection typically appear 4-10 days after being bitten by an infected mosquito.

The type of symptoms usually depend on the age of the person. People over age 50 and younger than age 15 are at greatest risk for developing severe disease. Severe cases of EEE infection begin with the sudden onset of headache, high fever, chills, and vomiting that may progress into disorientation, seizures, encephalitis (inflammation of the brain), and coma. Approximately a third of patients who develop EEE die, and many of those who survive have mild to severe brain damage.


Mosquito Life Cycle

There are four distinct stages in the life cycle of a mosquito – egg, larva, pupa, and adult. The mosquito has a different appearance at each stage. The entire cycle generally takes one to two weeks, but the time can vary depending on the species and environmental conditions such as temperature.

The adult female can produce eggs at intervals throughout her life, but she requires proteins from a blood meal in order for the eggs to develop. Depending on the species of mosquito, the female lays between 30 and 300 eggs at a time the Aedes mosquito, for example, generally lays 100 eggs at a time.

Many mosquitoes deposit their eggs directly on the surface of water, either singly (Anopheles) or clumped into rafts (Culex) others lay their eggs above the waterline, often in manmade containers (Aedes).

The water level must rise, as a result of rainfall or other means, to cover the eggs before the larva can hatch. The larvae feed on microorganisms in the water and go through a series of stages in which they molt and enlarge. At the end of this period, the larva changes into a comma-shaped pupa. The pupa does not feed and spends most of its time at the surface of the water.

When the pupa has matured, the pupal skin splits and a fully developed adult mosquito emerges. Adult mosquitoes feed mostly on flower nectar, but the females need to acquire a blood meal to continue the replication cycle.

If the female bites a person who is infected with Zika virus or another virus, the mosquito will pick up the virus. The virus reproduces within the mosquito for a certain period of time in which the virus migrates from the mosquito’s gut through the circulatory system to the salivary gland. Then, the mosquito can pass the virus to another person during a subsequent bite.

It is thought that warmer climates and denser population centers provide mosquitoes with greater availability to habitats in which they prefer to live and breed, especially for those species such as the Aedes mosquitoes that have adapted to human environments. Not only has the geographic range of mosquitoes expanded, but within urban areas there are more numerous sites containing standing water - such as buckets, flower pots, and old tires - that mosquitoes require to complete their life cycle.

These favorable settings accelerate the progression of mosquitoes through their life cycle, as well as shortening the incubation period within the mosquitoes that viruses need to reproduce.


Controlling Mosquitoes

Revised and updated by Elmer Gray and Ray Noblet University of Georgia Cooperative Extension Service and Department of Entomology

Mosquitoes can be a vexing and oftentimes serious problem. In homes, yards, and neighborhoods, mosquitoes can interfere with chores and spoil enjoyment of leisure activities. Some mosquitoes also transmit disease causing agents such as the protozoa that causes malaria and various types of viruses that cause disease in humans and horses, including West Nile virus and the new concern, Zika virus.

Larval Habits

In most parts of the United States, mosquitoes develop during the spring, summer, and fall. In warm, southern locations, they may develop throughout the year. Water is necessary for mosquito development (Fig. 1). Female mosquitoes lay their eggs on the surface of standing water or in places that later become flooded. Different species require different types of water habitats. There are 63 species of mosquitoes known in Georgia. Fortunately, only 10 to 12 are pests to man.

Examples of larval mosquito habitats include salt marshes, swamps, woodland pools, roadside ditches, artificial containers such as tires, buckets and planters, and water standing in various drainage systems. After the eggs hatch, larvae develop through 4 instars. Under ideal conditions of warm temperatures and abundant food, the larval stage may only require 5-6 days. After completing the larval stage, pupation occurs. The pupal stage is short in duration, typically requiring 2-3 days before the adult mosquito emerges onto the water’s surface. Overnight temperatures and the amount of food available to the larval stages play a significant role in determining how much time is required to complete the mosquito life cycle.


Figure 1. A typical mosquito life cycle.

Biting and Flight Habits

Both male and female mosquitoes feed on plant nectar to provide energy for flight. However, only females seek blood meals to acquire the nutrients needed to produce eggs. During blood feeding, females inject saliva to keep the blood from coagulating and aid ingestion. It is this saliva that causes the irritation and welt that is associated with mosquito bites. Most female mosquitoes seek a blood meal at dawn and dusk, but there are exceptions. The yellow fever mosquito, Aedes aegypti, and the Asian tiger mosquito, Aedes albopictus, will bite during the day, more commonly in shaded areas. Both of these species develop in artificial containers, and are especially attracted to standing water in tires, rain barrels and buckets. The Asian tiger mosquito was first found in Georgia in 1994, and is now a common pest in every county in the state. This species has become a much more serious nuisance than the yellow fever mosquito that developed in similar locations and has similar habits.

Most mosquitoes can easily fly 0.5-1.5 miles from their larval habitat to seek a blood meal. However, there is a considerable amount of variation in this area of mosquito biology. Salt marsh mosquitoes may fly 25-35 miles from their larval site, while aegypti and albopictus fly only a few hundred feet.

Disease

Mosquitoes can function as vectors for a variety of disease causing agents. Vectors pick up a disease agent from one host and carry it to another. Today’s concern about transmission of the Zika virus has raised awareness of this fact around the world. The Zika virus is primarily transmitted by the Aedes mosquitoes, with Aedes aegypti being the primary vector across the Caribbean basin and Central and South America. Georgia only has a remnant population of this species. Aedes albopictus has transmitted the Zika virus in some locations and is a potential vector in Georgia. Symptoms associated with the Zika virus include flu-like symptoms including headache, a progressive-itchy rash, fever and muscle and back pain. Many patients also report photophobia and conjunctivitis (red eyes), however, 80% of the people exposed to the virus show no symptoms. A significant concern about the Zika virus is the birth defect microcephaly in newborns. Sexual transmission from men to their partners has also been documented. Information related to the Zika virus is regularly being updated and should be monitored on the CDC and Georgia Department of Public Health websites.

There are several other viruses transmitted by mosquitoes in Georgia that can cause encephalitis (inflammation of the brain). The elderly, individuals with compromised immune systems, and children are usually the most susceptible. The most common types of encephalitis in Georgia are West Nile, LaCrosse and Eastern equine. Fortunately, transmission of viruses that cause encephalitis is rare in Georgia. Like encephalitis, yellow fever, dengue, and malaria were once common diseases in Georgia. However, they have long been absent. The mosquitoes that carried these diseases are still present, but in the absence of the disease agent and our general standard of living, cases of these diseases are limited to travel related occurrences.

Control

Because some mosquitoes can fly long distances, many communities in Georgia have organized mosquito control programs to provide area wide control. Support of your local program, if you have one, is your best option in preventing mosquito borne illness. Recent publicity about the Zika virus has renewed interest in mosquito control throughout the state. Integrated control programs operated at the community level will provide the most effective and efficient levels of mosquito suppression. However, in recent years many pest control operators have begun offering mosquito control services for individual home owners. These services can be effective, but should be based on Integrated Pest Management principles to assure effective and environmentally sound practices.

Many mosquito problems are caused by mosquitoes that develop in our own yards. If black and white-striped mosquitoes are biting during the day, you probably have the Asian tiger mosquito. As they don’t fly very far from their larval habitat, you could be raising them in your own yard. Below are methods you and your neighbors can use to reduce mosquito populations in your community:

  • Remove old tires or drill holes in those used for playground equipment to allow them to drain. Tires are common larval habitats for several mosquitoes that bite humans and should not be stored outdoors.
  • Check boats for holding water, clear drain holes, turn over, cover or increase angle to aid drainage.
  • Check tarps on boats or other equipment/items that may collect water in pockets or indentations.
  • Remove vegetation or obstructions in drainage ditches that prevent the flow of water.
  • Pick up broken, unused or discarded toys that hold water.
  • Pick up all beverage containers and cups.
  • Replace water in birdbaths once a week.
  • Replace water in pet and other animal feeding dishes or troughs at least once a week.
  • Fill tree holes (hardwood trees) that hold water with spray, insulating foam sealant.
  • Position garbage cans and lids so they don’t hold water.
  • Change water in planters, including hanging plants, at least once a week.
  • Maintain gutters so water drains properly.
  • Monitor all types of drainage pipes/systems for standing water.
  • Fix dripping outdoor faucets that create pools of water.

You can avoid or repel mosquitoes by the following:

  • Keep door and window screens in good repair.
  • Screen doors should open outward and have automatic closing devices and latches to prevent them from being accidentally left ajar.
  • Wear protective clothing, loose fitting, long pants, long-sleeve shirts, shoes and socks during times and in locations of high mosquito incidence. Mosquitoes are less attracted to light clothing than dark. Be aware, mosquitoes can bite through T-shirts and other lightweight, tight-fitting clothing.
  • During periods of excessively high mosquito incidence, stay indoors as much as possible.
  • Use an EPA approved (DEET, IR3535, Picaridin, Oil of Lemon Eucalyptus) insect repellent before going into high-risk areas or when outside during high-risk periods (dawn and dusk) when mosquitoes are present. Follow the directions carefully. Mosquitoes will bite unprotected areas, so complete coverage is imperative. Don’t allow repellent to get in your eyes, mouth, or nose. The American Academy of Pediatrics recommends the use of repellents containing 30% or less of DEET on children 2 months or older. Children should NOT be allowed to apply repellents to themselves. Repellents should be applied to an adult’s hands and then applied to the child. The repellent should not be applied to the child’s hands and the treated areas should be washed after leaving the mosquito infested area.
  • Permethrin based repellents can be used on clothing only. For maximum protection use an approved repellent on the skin and permethrin on clothing.
  • Citronella based products are effective in repelling mosquitoes in protected areas of minimal air flow.
  • Repellent lanterns and personal devices using a heat source and a repellent treated pad or wick have been demonstrated to be highly effective at repelling mosquitoes from small areas
  • Do not rely on electronic bug killers or ultrasonic (sound) repellents for protection. They have not been scientifically proven to be effective.
  • Mosquitoes don’t like strong wind currents. Sitting by a fan will repel them.
  • Call the environmental health unit of your county health department to find out if there is a mosquito abatement program (spraying) in your area. If not, extra care in following these recommendations may be warranted.

There are a variety of methods to suppress mosquitoe populations:

  • The first step is to eliminate all sources of standing water.
  • Fish are highly effective predators and will control mosquitoes in most sites where fish occur.
  • Larval habitats that cannot be eliminated should be treated with an EPA approved larvicide if mosquito larvae are present. Products with the biological control agent Bacillus thuringiensis var. israelensis are safe and effective and available at local home and garden stores.
  • Pyrethrin aerosols will kill mosquitoes in the house.
  • Hand held fogging devices using a pyrethroid based insecticide can be purchased from hardware and garden shops to give temporary control outdoors. Be sure to buy the insecticide that is recommended with the device.
  • Residual insecticides (bifenthrin, permethrin, cypermethrin) can be applied to areas where mosquitoes rest during the heat of the day. Sites may include shrubbery, ground covers and underbrush.

A Problem

If your community has an organized mosquito program, it can be effective in greatly reducing mosquitoes that bite in the evening. These are usually controlled by applying ultra-low volume (ULV) sprays in the evening that drift through the area killing flying evening mosquitoes. The day biting Asian tiger mosquito and yellow fever mosquito are resting in the foliage and other protected areas in the evening and are not as susceptible to the spray as mosquitoes that are active during this period. If the ULV application is conducted during the day for these mosquitoes, rising air currents from the heat of the sun will cause the spray to go upward and be ineffective, rather than drift low to the ground as it does in the evening. The day biting mosquitoes can only be targeted with ULV sprays during the first and last hour of daylight when conditions are typically conducive for effective applications.

Since conventional adult spraying is difficult to conduct effectively to control the daytime biters, eliminating their larval habitats is the best option. Unfortunately, government mosquito programs are not likely to enter private property to treat containers. This means you will need to control these mosquitoes yourself.

Remember, the day biters don’t typically fly far (100-300 yards) from their larval habitats. If you or your neighbors remove, cover or empty containers that contain standing water, you can greatly reduce your problem. You should not have expectations that a city or county mosquito program will be able to control these day biters for you.

Summary

With each spring, public awareness is renewed of the threat from mosquitoes and mosquito-borne diseases. In the years past, the greatest importance mosquitoes had in Georgia was the discomfort from their biting. Unfortunately, this is not the case anymore. The introduction of the West Nile virus and the potential threat posed by the Zika virus have increased the public’s awareness about the serious nature of mosquito populations. By eliminating the larval habitats on your property and taking a few simple precautions, you can reduce the threat of mosquito-borne illness and annoyance in and around your home and neighborhood.

Revised and updated by Elmer Gray and Ray Noblet, University of Georgia, Cooperative Extension Service and Department of Entomology. May 31, 2016.


Bloodsucking

Mosquitoes use exhaled carbon dioxide, body odors and temperature, and movement to home in on their victims. Only female mosquitoes have the mouth parts necessary for sucking blood. When biting with their proboscis, they stab two tubes into the skin: one to inject an enzyme that inhibits blood clotting the other to suck blood into their bodies. They use the blood not for their own nourishment but as a source of protein for their eggs. For food, both males and females eat nectar and other plant sugars.


Dengue & Mosquitoes

People contract Dengue from the bites of infected Aedes aegypti or Aedes albopictus mosquitoes. Mosquitoes become infected when they bite a person who has dengue virus in their blood.

In rare instances, dengue can be transmitted from transplanted organs, blood transfusions from infected donors or from a dengue-infected pregnant mother to her fetus. There are four viral types of dengue, but the most severe form of this disease is called Dengue hemorrhagic fever (DHF). Untreated persons, especially children, risk death as a result of infection.

WHAT TYPE OF MOSQUITOES TRANSMIT DENGUE?

WHERE ARE THEY TYPICALLY DISTRIBUTED?

These two species of mosquitoes are distributed worldwide and are found within the U.S.

SYMPTOMS OF DENGUE FEVER AND DHF

  • High fever
  • Severe headache with pain behind the eyes
  • Joint discomfort
  • Muscle and bone pain
  • Rashes
  • Mild bleeding from the nose or gums

Milder illnesses occur in people with their first infection, while older children and adults show more severe symptoms.

DHF symptoms include a fever that lasts from 2-7 accompanied by similar symptoms seen in dengue fever. But, when fever declines, serious symptoms may begin to occur.

  • Continuous vomiting
  • Severe abdominal pain
  • Breathing difficulties
  • Failure of the circulatory system
  • Even shock and death, if not treated

IS DENGUE IN THE US?

While Aedes aegypti and Aedes albopictus are common in southern U.S. territories, dengue transmission remains infrequent within the continental U.S. primarily due to the fact people rarely come into contact with vectors. For this reason, nearly all dengue cases reported in the 48 continental states were acquired elsewhere by travelers or immigrants.

PREVENTION & TREATMENT OF DENGUE

No vaccine is available for dengue fever, and no medications exist to treat dengue infections. This makes prevention the most important step, and prevention means avoiding mosquito bites by using insect repellents, wearing long sleeves and long pants and eliminating the containers that hold water and give the aquatic stages of the mosquitoes a place to develop.

There is also no specific medication or vaccine for treatment of dengue fever or DHF, so a person with dengue should see a doctor for treatment. They should also rest and drink plenty of fluids. DHF can be treated by aggressive replacement of fluids if an early clinical diagnosis is made. Treatment of those with DHF will almost always require hospitalization and extensive supportive care.


Should I worry about mosquito bites?

Mosquitoes are small flying insects. Female mosquitoes have a long, piercing mouthpiece, with which they pierce the skin to consume their blood. Some mosquito bites are harmless, but others carry dangerous diseases.

It is only female mosquitos that bite people. Blood serves as a source of protein for their eggs. Male mosquitoes do not consume blood.

Mosquito bites pose a considerable health risk, with mosquito-borne diseases causing millions of deaths a year worldwide. Malaria, one of the most commonly known diseases unique to mosquitos, killed around 438,000 people globally in 2015.

However, a person can take preventive measures to keep them at bay. This article explores the symptoms and risks, as well as how to avoid bites.

Share on Pinterest A mosquito bite might lead to a severe infection.

Symptoms of a mosquito bite occur shortly after being bitten. A round, red bump with a dot in the middle usually accompanies an itching sensation.

Other signs of a mosquito bite include:

  • dark spots that resemble bruising
  • swelling or redness
  • small blisters in place of hard bumps

Multiple bumps are also common. These indicate that a mosquito pierced the skin in more than one location, or that more than one insect bit the person.

Children and people with weakened immune systems can experience extra symptoms, such as hives, swollen glands, and low-grade fever.

In general, symptoms become less severe with additional bites. This is because the body slowly acclimatizes to the bites.

According to the American Academy of Allergy, Asthma, & Immunology (AAAAI), a mosquito bite might cause anaphylaxis in rare cases. This is a potentially life-threatening condition that causes throat swelling, hives, faintness, or wheezing.

The risk of developing a serious disease is the most dangerous outcome of a mosquito bite.

There are several harmful infections that mosquitoes can carry and transmit, including:

  • Malaria: Parasites cause this life-threatening disease by infecting and destroying red blood cells. To control and treat malaria, early diagnosis is crucial.
  • West Nile virus: Most people with West Nile Virus show no symptoms, although some develop a fever or other flu-like symptoms. For a small number of people with the virus, a serious illness develops in the nervous system.
  • Zika virus: This is a generally mild condition that initially causes fever, joint pain, and rash. The initial symptoms of Zika usually pass after 1 week, but the disease can lead to congenital anomalies if a woman becomes pregnant after receiving a mosquito bite.
  • Yellow fever: This virus causes inflammation in the brain and spinal cord. Its symptoms include fever and sore throat.
  • Dengue fever: This disease can trigger high fever, rash, muscle soreness, and joint pain. In the most extreme cases, severe bleeding, shock, and death can occur. Dengue fever is mostly active in tropical and sub-tropical regions.
  • Chikungunya: Joint pain, headache, rash, and fever are common in chikungunya. People with the disease require bed rest and fluids for recovery.

If a person notices a mosquito bite and feels any flu-like symptoms or a fever, they should seek medical treatment immediately.

Female mosquitoes tend to target some people over others when it comes to feeding. Researchers do not yet fully understand the reasons for this selective process.

One 2013 study noted that mosquitos have sensors that pick up on carbon dioxide emissions and body odor. They can then identify which nearby people would make a suitable feeding ground.

Body heat, movement, and body odors, such as sweat and lactic acid, might also play a role in attracting mosquitoes.

Preventing mosquito bites is always more effective than trying to treat them, given the potential seriousness of the diseases that can transmit during the bite.

The Environmental Protection Agency (EPA) advise that mosquitoes need water to breed. Removing sources of standing water around the home and garden can reduce the number of mosquitoes in the area.

The following steps can help prevent bites:

  • Use screens and netting.
  • Cover up the skin when outdoors.
  • Avoiding wooded and grassy areas.
  • When planning to be in mosquito-dense areas, avoid bright clothing, perfumes, and scented beauty products.

Repellents

Using insect repellent may be necessary when doing activities that naturally increase carbon dioxide emissions and bodily odors, such as exercising outdoors.

The Centers for Disease Control and Prevention (CDC) recommends a number of effective options for repelling mosquitos.

N,N-Diethyl-meta-Toluamide (DEET) is one of the most commonly used chemical-based mosquito repellents. Studies show that it is one of the most effective on the market.

DEET works by interfering with the receptors in the mosquito that detect carbon dioxide and body odor, causing them to not detect the person wearing DEET as a potential source of nutrition.

According to the U.S. Environmental Protection Agency (EPA), DEET provides protection against mosquito bites for between 2 and 12 hours, depending on the percentage of DEET in the product.

DEET is available in various forms, including liquids, sprays, lotions, and wristbands.

Always follow the directions on the label when using DEET products.

Picaridin is a newer type of insect repellent. Working in the same way as DEET, it prevents the mosquito from recognizing its prey.

A 2018 meta-analysis shows that the preventive effects of picaridin last for more or less the same amount of time as DEET.

Picaridin is a safe option for children under 6 months of age , as it contains fewer potentially toxic qualities than DEET.

Oil of lemon eucalyptus

Oil of lemon eucalyptus may be a good option for those who prefer a natural, chemical-free repellent.

Repel and Off! Botanicals are examples of products that contain this natural oil.

Travel advice

People who are planning a vacation should learn about the risk of mosquito-borne illness at their intended destination.

They should also speak with a healthcare provider before traveling. There may be optional or mandatory vaccinations or medications available to protect against certain mosquito-borne diseases, such as yellow fever or malaria.

Remember also to pack an effective insect repellent.

Where possible, choose accommodation with air conditioning or window and door screens, or sleep under a mosquito bed net.


Vaccination for Travel: Other Rare Diseases

Vaccination for certain other diseases considered rare or “disappeared” in the United States is only recommended if you are traveling to an area of the world in which that disease is widespread. The U.S. immunization schedule, for example, does not recommend routine vaccination for yellow fever however, if you are traveling to areas of the world where the disease remains endemic, you may be recommended—or even required—to get the vaccine. Travel to certain countries in South America and sub-Saharan Africa requires a yellow fever vaccination.

The vaccination recommendations for yellow fever—a virus spread by the bite of infected mosquitoes—differ from those for other “rare” (in the United States) diseases like polio and measles primarily because of the difference in how they spread. Measles and polio can spread directly from one human being to another a single infected traveler entering or returning to the U.S. could expose everyone he or she came in contact with to the disease. Yellow fever, however, cannot be spread directly between humans. The virus can only be transmitted by the bite of a particular type of mosquito that’s been infected—and then only if the mosquito fed off an infected host a certain period of time before biting its latest victim. Therefore, yellow fever can spread relatively easily in areas with both large mosquito populations and a large number of infected humans on which the mosquitoes can feed, but not in areas without them. In the United States, the last yellow fever outbreak was in New Orleans in 1905. Two fatal cases were reported in the 1990s, both in U.S. residents returning from trips to South America. [2] Neither had been vaccinated.

The Centers for Disease Control and Prevention website offers information about vaccinations for travelers. You can find more information here.


Find a Specialist Find a Specialist

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

  • To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from MedlinePlus Genetics.



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