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20 Major Diseases Birds Carry: A Complete Guide

sick seagull

If you live in a city or major town, you are at risk for contracting one of the nearly 70 diseases and parasites that pest birds carry. This is because the droppings of these diseased birds are easily disturbed by animal activity or wind and can spread illness to people. The good news is that if bird activity near your work or home is taken care of right away, then you will be less likely to contract an infection or develop pest infestations. Here's our guide on how to identify which illnesses birds can carry so that they don't get too close for comfort! While it is true that scientists have identified nearly 70 viruses, fungal and bacterial infections, pests and parasites that birds carry and can transfer to humans and other animals, many of them are minor threats and are oftentimes not even noticeable to those who contract them. However, the remaining 20 can be quite detrimental to one's health or life and should be mentioned more often, in order to raise public awareness of the risks associated with living alongside pest birds.

Table Of Contents


Histoplasmosis is the most frequently spread disease that transfers from birds to humans. Histoplasmosis is an infection caused by a fungus that grows in bird or bat droppings. Breathing in the spores can cause people to become sick. Although most individuals who breathe in the spores do not get ill, those who do may experience a fever, cough, and tiredness.

Many individuals who contract histoplasmosis will recover without medication but immunocompromised individuals often fall seriously ill, sometimes for over a month. To treat severe histoplasmosis in the lungs, chronic histoplasmosis, and infections that have spread from the lungs to other regions of the body, a prescription antifungal drug is required. Oftentimes people require the medication from 3 months to a full year.


Candidiasis is a condition caused by a yeast (a type of fungus) known as Candida. Candida albicans is the most common species that causes infection in people and is also the strain that can be carried in birds and spread through their droppings, as its focus is on the birds' digestive tract.

Known as invasive candidiasis, this is an infection that affects many areas of the body, including:

  • Bloodstream

  • Heart

  • Eyes

  • Bones

  • Brain

  • Throat

Reducing sugar intake immediately will significantly decrease the speed at which the fungus spreads since sugar is its main source of energy. In addition, antifungal medication will be needed to resolve the illness.

NOTICE: According to the CDC, a new multi-drug resistant strain of Candida known as C. Auris is rapidly spreading through the United States, despite quarantine for Covid 19 this past year. Some versions of this new strain are resistant to all 3 antifungal medications known to treat Candidiasis and are considered threat level URGENT by the CDC.


Cryptococcosis is a fungal infectious disease caused by pathogenic encapsulated yeasts in the genus Cryptococcus with a worldwide presence and a variety of common symptoms. This fungus can often be found in a variety of bird droppings, mainly pigeons, but also in some parrots, chickens, sparrows, and starlings. Currently, there are two species of Cryptococcus that cause illness in humans: Cryptococcus neoformans and Cryptococcus gattii.

One thing that makes this infection unusual is the incubation period. After inhaling the spores, it can take between two weeks to three years to develop an infection, with the average being 6 months. This means it is sometimes very difficult to discern where you were exposed to the spores in the first place.

C. neoformans infection in the lungs can cause a pneumonia-like illness. The symptoms are often similar to those of many other illnesses, and can include:

  • Cough

  • Shortness of breath

  • Chest pain

  • Fever

C. gattii is similar in that it can cause a pneumonia-like illness as well, but it has the tendency to infect the central nervous system and brain. The symptoms of this infection are often more serious than those from C. neoformans and can include:

  • Headache

  • Mental confusion

  • Disorientation

  • Nausea and vomiting

  • Light sensitivity

St. Louis Encephalitis

Often, the transmission of this virus to humans is through mosquitos, but the original host to the virus is birds. Birds that are infected develop high levels of the virus in their bloodstream, and mosquitos that get the virus from these birds then spreads it to humans.

More often than not, those infected with this virus do not develop symptoms, but those that do will experience fever, headache, nausea and vomiting. Those that are at most risk of developing serious complications from this virus include the elderly or those with weakened immune systems.

It is important to note that while most cases of St Louis Encephalitis will resolve on their own over time (lasting several days), it can take up to a month for some and may require over the counter medication and hospitalization in serious cases.

The best way to avoid this illness is to avoid mosquito bites, but it is worth knowing that the primary reason this virus can spread so much is because of birds being the perfect host for the virus.


Infections caused by a variety of species of salmonella, a bacteria common in the digestive tracts of animals and birds, including chickens. It is estimated that one billion people worldwide are infected with this pathogen every year.

Salmonella infections often affect areas where there is a water shortage or low sanitation standards in place because these conditions allow for large amounts of pathogens to spread quickly.

Recently, in May of 2021, the CDC performed an investigation into songbirds that they believed were spreading this bacteria, and found it was being spread to humans through bird feeders and birdbaths, which can become contaminated by bird droppings. Ensuring these objects are cleaned on a regular basis and that birdbath water remains clean not only keeps you safe from contracting this illness but it lowers the risk of it being spread amongst other birds as well, protecting bird populations from a major outbreak.


More often known by the name E. coli, this bacteria can cause infection when consumed or if it comes in contact with an open wound. It is commonly found in the digestive systems of poultry, pigs and humans, but birds are one of its more common hosts. It is present in all bird environments, especially droppings, and in poultry house dust. Often antibiotics are used to prevent the spread of this infection through feed or droppings.

Different strains of E coli can lead to different symptoms based on how your body reacts to them, making accurate diagnosis difficult without a doctor performing tests. It can include symptoms such as:

  • Stomach cramps

  • Diarrhea

  • Vomiting

  • Fever

  • Kidney failure

While oftentimes the infection resolves itself within a week and more serious symptoms don't develop, for those with weakened immune systems and children, the risk of it becoming more serious and life threatening increases significantly.

Ensuring you wash your hands after touching raw meat or eggs, as well as avoiding contact with any bird droppings, is the best way to avoid contracting this infection.

West Nile Virus

The West Nile Virus is a disease that occurs in birds and is spread to people by mosquitos. Birds are infected with this virus when they eat an animal carrying the virus or if insects bite them while they have it in their bloodstream.

Most humans who contract West Nile Virus experience no or mild symptoms such as fever, headaches, body aches, vomiting and diarrhea, and recover on their own within a week.

However, for every 150 people who contract it, one person develops severe symptoms, including:

  • Encephalitis

  • Meningitis

  • High fevers

  • Disorientation

  • Coma

  • Tremors

  • Convulsions

  • Vision loss

  • Paralysis

Opposite to St Louis Encephalitis, this disease spreads through birds but originates in mosquitoes, and the birds contract the illness when bitten by an infected mosquito. While barely any human cases are fatal, for birds it's another story. over 300 species of dead birds inspected since 1999 have been found to contain West Nile virus, and primarily birds like crows and the around 40 species of Jaybirds once contracting the virus often die.


Psittacosis is a disease caused by a type of bacteria known as chlamydia psittaci, which can be spread to humans through contact with infected birds. It is known as Chlamydiosis when in birds, but is also referred to as ornithosis and parrot fever due to the fact that it mainly affects pet birds like parrots and canaries. Other types of birds, including chickens and ducks, are also known carriers of the disease. This disease is spread when the bacteria are inhaled or when it comes in contact with an open cut. It is often confused with the flu as its symptoms often mirror that of the flu.

Symptoms of this disease include:

  • Fever and chills

  • Muscle ache

  • Cough

  • Headache

  • Tiredness and fatigue

While there are typically very few confirmed cases of Psittacosis, with less than 10 cases per year, in 2018 there was an outbreak in a poultry farm that led to 13 confirmed cases among the workers there. Ensuring cleanliness and consistent disinfection of any dangerous materials like feathers and bird droppings while preventing anything from becoming airborne (i.e. don't use a vacuum or dry duster) is often all you need to avoid contracting this illness.

Chickens in a Row

Avian Tuberculosis

This is a disease caused by the bacteria Mycobacterium avium and can affect a wide range of birds and mammals, including humans. Often it is spread when the bacteria is inhaled and it spreads to one's lungs.

This disease is spread through the droppings of infected birds, so anything that comes in contact with their feces is a risk factor for contracting this disease. What allows this to spread further than it should is the fact that it can survive for as long as 4 years in droppings, infected soil, or another organic material. It also has a long incubation period in birds, so symptoms don't appear until months after the initial infection. Symptoms of this disease are often minor and include:

  • Mild fever

  • Diarrhea

  • Vomiting

  • Dehydration

  • Headaches

Treatment of this illness is accomplished by taking antimicrobial medications and often doesn't last longer than a few weeks.

Avian Flu

Avian Flu, or avian influenza, is a disease that occurs naturally among wild aquatic birds and is also known to infect poultry and other bird species. While it does not normally infect humans, there have been enough cases of Avian Flu in humans for people to be wary when in an environment that wild birds frequently inhabit. Birds and people contract this virus when they come into contact with infected bird droppings, saliva, or mucus. It is not known to spread between humans, but it is something that is continuously monitored in case a change is noted. When humans become sick from it symptoms include:

  • Conjunctivitis

  • Sneezing or coughing

  • Runny nose

  • Low fever

  • Muscle aches

In more serious cases, tiredness, weakness and confusion are also seen, as well as respiratory failure, and seizures. If any of these symptoms develop, it is recommended to immediately seek treatment. It can become worse if not treated quickly, so seeing the doctor as soon as possible is key for your health.

The most effective method to avoid infection with avian influenza A virus is to prevent contact with infected birds. Direct or close contact with contaminated poultry is the most common cause of human infections with avian influenza viruses.

Avian Pneumoencephalitis

Also known as Newcastle Disease, this is a viral disease that most notably affects the respiratory system of birds, including caged and domestic ones. Should poultry farms not use vaccines or antibacterial medication, they often risk losing the entire flock to the disease because it spreads too quickly to be controlled once symptoms begin. This disease is most commonly spread through contact with infected birds or their droppings. While this often causes younger birds including chickens to become seriously ill and is often fatal, when infection occurs in humans, the only symptoms commonly seen are either conjunctivitis, laryngitis, or mild flu-like symptoms.

An interesting fact about this virus is that in humans, it actually replicates more quickly in cancer cells than in healthy human cells, and like other viruses, it kills the host cell during replication. For this reason, scientists are looking into this virus as a potential cure or alternative treatment for cancer.


This is a protozoan parasite that affects the digestive tract of many species of animals, including cattle, sheep, rodents, cats and dogs, birds, and humans. When birds contract this parasite, it is spread when their droppings enter a body of water, which then can further spread through any animal that ingests contaminated water. Millions, sometimes tens of millions of oocysts (spores containing zygote of a parasitic protozoan) can be dispersed through a single bowel movement of an infected animal, allowing the parasite to spread rapidly. It has even been proven to be resistant to chlorine for long periods of time, which is why you should always avoid allowing ducks or other waterfowl to hang around your pool, and if they do, thoroughly clean it before using.

The symptoms of this parasite are focused on the small intestine, as that is where the infection thrives. Symptoms include:

  • Stomach cramps

  • Dehydration

  • Diarrhea

  • Nausea & vomiting

  • Fever

  • Weight loss

These symptoms can last around 2 weeks on average and often those with healthy immune systems recover on their own without treatment. The key factor in quick recovery is drinking plenty of fluids to avoid dehydration.

Allergic Alveolitis

Believe it or not, birds actually have their own type of dander, and it contains different proteins than those found in mammals. These can cause allergic responses when inhaled by certain humans, and this disease is commonly referred to as bird fancier's lung or farmer's lung.

The symptoms of this illness are very similar to what you would expect from other respiratory diseases like asthma or pneumonia, such as

  • Chest pain

  • Dry cough

  • Shortness of breath

  • Bronchitis

You will not develop this reaction after one or two exposures to bird dust or dander, but consistent and prolonged exposure causes this to develop in up to 50% of individuals. Oftentimes it is a minor reaction, but in more severe or chronic responses, you could be dealing with chronic bronchitis and lung fibrosis, resulting in permanent lung damage. In places like cities where pigeons or seagulls are prevalent, the chances of consistent exposure that could result in developing this reaction significantly increases. Dealing with bird infestations the second you see them begin is the main way to prevent anyone in the area from developing this reaction.

Immediately eliminating exposure to bird dust and dander is key to the improvement of symptoms, and if it's a more serious case, doctors may recommend medications that make breathing easier.

Bed Bugs

Bed bugs are often carried by birds, bats, and even rodents. Not only can they make your life a nightmare by keeping you up at night with constant itching from their bites, but they also carry over thirty human pathogens on their bodies that could infect anyone who comes into contact with them or the bacteria left behind in an infested area.

The signs of a bed bug infestation include:

  • Small, itchy bumps on the skin

  • Extreme itching and rashes

  • Bumps in groups of two or three (bites)

  • Distinctive blood smears in areas where they tend to hide around mattresses, sheets, pillows etc. These are small black stains left behind that look like rust spots when you swipe them away.

Often the species of bird that will carry bed bugs are swallows and chimney swifts. While species of bed bugs vary, and some only prefer birds, the type that are most prevalent throughout the human population is also known to latch onto other mammals and birds. If you find you have both a bed bug infestation and either swallows or chimney swifts roosting nearby, the focus should be on eliminating both, as the birds will easily allow bedbugs to spread again.

Chicken Mites

Chicken mites are a type of bird mite that tend to infest poultry, but have been known to bite humans on occasion, leading to skin irritation. Chicken mites cause extreme discomfort amongst poultry farms, and signs of a chicken mite infestation include:

  • feather loss

  • scabs near the base of feathers

  • eggs on chicken feathers

  • the appearance of dirty feathers where they leave droppings

  • anemia in the birds

  • death

While most cases are caught and dealt with before the more serious symptoms arise, it is important to know that if not eradicated quickly they will spread throughout the poultry farm population or backyard flock and can be very difficult to eliminate. Silkies and polish chickens are especially prone to developing this pest infestation.

Some tips for prevention include adding diatomaceous earth or wood ash to the dust baths chickens are known to take, as this can suffocate and kill any mites that may have found their way onto your chickens.

Cleaning your coop and ensuring an overall clean environment for your chickens is always the best way to avoid ever having to deal with this obnoxious pest.

Bird Mites

Similar to chicken mites bird mites are tiny eight-legged parasites that feed mainly on the blood of their host. While most bird mite bites won't lead to any serious consequences, they still can be very itchy and difficult for some people. Bird mites require blood from birds to reproduce, therefore they cannot thrive away from birds for a long time. However, they are known to bite humans out of aggression which can result in red swollen itchy skin and other types of skin irritation.

The best way to deal with a bird mite infestation is the same as dealing with other mites: consistent and disinfecting of surfaces, ensuring and areas that birds have come in contact with are immediately cleaned, and if you see any nests around your home or property, especially if it been there for a long period of time, relocate it far away from your home, or if it's empty, dispose of it. Often sparrows, starlings, and pigeons will consistently reuse the same nest throughout the year, allowing droppings to pile up and create the perfect breeding ground for bird mites.

Overpopulation can occur in areas like this, at which point the mites will spread in search of new hosts, and can take up residence in buildings and homes as a result. This often occurs in late spring to early summer, and has been found to take up residence on animals like mice and rats when birds are not present.

Yellow Mealworms

While not the most dangerous of pests, the yellow mealworm is nevertheless something that can become very irritating for humans. Yellow mealworms are actually the larvae of beetles and hatch from eggs laid in bird nests, compost heaps, and other areas that are rich with decaying matter. When feeding on matter that contains bird droppings, they can become infected with pathogens such as E. coli or salmonella, and can transmit them to any animal that eats these pests, often other birds, allowing the cycle of disease transmission to continue.

When present around poultry farms, and allowed to develop into fully grown beetles, they develop a chemical that causes irritation in humans, often appearing as asthma or allergy-like symptoms.

While legal in the United States, in other countries like the UK and the EU it is illegal to feed these mealworms to chickens meant for human consumption, as there is a large risk of disease being spread from mealworms to chickens, and then to humans.


Birds are known to spread fleas in a number of ways, one such way is to carry them on their bodies and then transfer them onto surfaces in the coop or nesting area. The larvae of bird fleas will feed on the bird's nesting material, but once grown will be able to reproduce and attach to young birds in the nest. As a result of this reproducing cycle, large infestations can occur in a flock of birds which can spread the fleas in any area that they roost. If you have pigeons, sparrows, starlings or other pest birds roosting or nesting near your property, be wary that they could potentially bring a major flea infestation to your pets or home.


Bird lice are parasites that live primarily on the bodies of birds. Lice are usually spread between individuals, especially those in close quarters with one another, but can also be spread to individual birds via contact with infected animals, nests or even surfaces like tree branches. Should birds remain for long periods of time near buildings, or populated areas, lice can spread from the infected birds through vents, openings, and on clothing and can spread diseases to humans.

If you have a bird problem, we can help. AviAway professionally installs bird control solutions for all bird species. We have 30+ years of experience in bird control and have performed work for companies like Amazon, Rite Aid, and the U.S. Postal Service. Click here or call 844-247-3373 to request a free bird control quote.


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