Some diseases, known as zoonotic diseases, can be transmitted from wildlife to humans. Fortunately, in Massachusetts many of the most prevalent zoonotic diseases are easily preventable, identifiable, and treatable. Learn about the transmission, symptoms, and prevention of these common diseases.
Giardia Lyme Disease Rabies West Nile Virus Eastern Equine Encephalitis Zika Virus
GIARDIA
Giardia lamblia is a common single-celled parasite that can cause an illness of the intestines known as Giardiasis. The disease can be found throughout the world and is widespread among mammalian, avian, and reptile species.
Giardia and Beaver
While there has never been a proven, documented case of a human contracting Giardia from beaver, the species has often been unfairly and inaccurately implicated as the source of Giardia contamination of freshwater resources. However, current research shows that contamination from humans is regarded as a more probable source. In fact, humans are now considered to be the most common reservoir of Giardia, as they shed 900 million cysts per day.
Transmission
- Swallowing contaminated food or water. Once swallowed, the parasites multiply in the small intestine and pass through the bowels.
- Eating or touching your mouth with unwashed hands
- Spreading germs via person-to-person contact
Symptoms
Usually appear 9-12 days after exposure, but can appear anywhere between 5-25 days.
Symptoms can include:
- Diarrhea
- Bloating
- Stomach or abdominal cramps
- Nausea and vomiting
- Dehydration (loss of fluids)
- Weakness and fatigue
- Loss of appetite and weight loss
- Less common symptoms include itchy skin, hives, and swelling of the eyes and joints
Treatment
Some individuals recover without the need for medication.
Prevention
- Frequent hand washing
- Wearing gloves when handling possibly contaminated materials
- Careful disposal of sewage wastes and protecting water supplies from human, companion animal, and wildlife contamination
- Avoidance of drinking water that has not been treated or filtered
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LYME DISEASE
The bacterium that causes Lyme disease can be spread to both people and animals through the bite of very small, infected ticks. These ticks require constant, high relative humidity at ground level, and therefore are most common in the northeastern and coastal states, the upper Midwest, and the Pacific Northwest. Lyme disease is most often spread during the late spring through the early fall seasons. Ticks live on low-lying brush and grassy areas, and crawl onto animals and people who come into contact with these plants.
Although people generally associate deer with Lyme disease, at least 27 species of mammals serve as efficient hosts for deer ticks, and over 125 vertebrate species serve as effective hosts for nymphs (immature ticks).
Transmission
Transmission occurs through the bite of an infected deer tick:
- The tick usually must be attached to a person for at least 24 hours before it can transmit the bacteria
- Young ticks are most active during the warm-weather months between May and July. Adult ticks are most active during the fall and spring. Ticks may also search for a host any time that winter temperatures are above freezing.
- For Lyme disease to exist in an area, three elements must be present in the natural environment:
- Animals that are infected with Lyme disease bacteria,
- Ticks that can transmit the bacteria, and
- Animal hosts (such as mice and deer) that can provide food for the ticks in their various life stages.
Symptoms
Early Signs and Symptoms (3 to 30 days after tick bite):
- Rash (erythema migrans) where the tick was attached. It often, but not always, starts as a small red area that spreads outward, clearing up in the center so it looks like a donut or bullseye. This is the most common symptom and occurs in 70-80% of infected individuals.
- Flu-like symptoms – fever, chills, headache, fatigue.
- Muscle and joint aches.
- Swollen lymph nodes.
Later Signs and Symptoms (weeks to months after tick bite):
- Severe headaches and neck stiffness
- Additional rashes on other areas of the body
- Arthritis with severe joint pain and swelling, particularly the knees and other large joints
- Bell’s palsy (loss of muscle tone or drooping on one or both sides of the face)
- Intermittent pain in tendons, muscles, joints, and bones
- Heart palpitations or an irregular heart beat (Lyme carditis)
- Episodes of dizziness or shortness of breath
- Inflammation of the brain and spinal cord
- Nerve pain
- Shooting pains, numbness, or tingling in the hands or feet
- Problems with short-term memory
Treatment
- Prescribed antibiotics.
- Early detection and treatment can prevent more serious problems from occurring.
- If you notice a bullseye or donut-shaped rash or develop symptoms of Lyme disease after being in an area with ticks, contact a doctor as soon as possible.
Prevention
- After being in an area with ticks, do a thorough tick check of the body. Ticks often gravitate toward the legs, thighs, armpits, ears, groin, and hairline. They are very small, and in the nymph stages are no larger than the head of a pin.
- Remove ticks safely:
- Use fine-tipped tweezers to grasp the tick as close to the skin’s surface as possible.
- Pull upward with steady, even pressure. (Don’t twist or jerk the tick as mouth-parts may break off and remain in the skin. If this happens, remove the mouth-parts with tweezers. If you are unable to remove the mouth easily with clean tweezers, leave it alone and let the skin heal.)
- After removing the tick, clean the bite area and your hands with rubbing alcohol, an iodine scrub, or soap and water.
- Dispose of a live tick by submersing it in alcohol, placing it in a sealed bag/container, wrapping it tightly in tape, or flushing it down the toilet.
- Take the following precautions when you are outside in an area likely to have ticks, such as brushy, wooded, or grassy areas:
- Use a repellent with DEET (except on infants under two months of age).
- Use permethrin products on clothing, shoes, bed nets, and camping gear (not on skin).
- Wear long sleeves and long, light-colored pants tucked into your socks or boots.
- Stay on cleared trails when walking or hiking, avoiding the edge habitat.
- Talk to your veterinarian about tick control options (tick collars, repellents) for your pets.
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RABIES
Rabies is a much-feared disease of the nervous system. Rabies was rare in Massachusetts for decades, appearing primarily in a very small percentage of bats. However, an outbreak of raccoon rabies, which originated in the mid-Atlantic states in the late 1970s, made its way to New England. It is one of several strains of rabies impacting wildlife in the United States.
You cannot tell if an animal has rabies just by looking at the animal. Some infected animals may act strangely or aggressively, but others may not.
All mammals can contract rabies, but the current outbreak primarily affects raccoons, bats, skunks, foxes, and occasionally woodchucks. Birds, rabbits, opossums, squirrels, chipmunks, rats, mice, and other small rodents are rarely affected. Snakes, turtles, lizards, frogs, toads, salamanders, fish, and insects do not get rabies.
Transmission
- Through contact with the infected saliva of a rabid animal
- Commonly from an animal scratch or bite
Symptoms
- Flu-like symptoms (which may last several days) such as general weakness or discomfort, fever, or headache
- Discomfort or a prickling or itching sensation at the site of bite
- Delirium, abnormal behavior, hallucinations, and insomnia as disease progresses
Treatment
- Shots of immunoglobulin can be given around the bite or scratch to help fight the virus. Individuals will also receive 4 or 5 vaccinations in their arm over several weeks. The shots can help to prevent rabies if administered before the person starts to get sick.
- For individuals who do not receive the shots and become sick with rabies, there is no effective treatment and survival is rare. The acute period of disease typically ends after 2 to 10 days. Once clinical signs of rabies appear, the disease is nearly always fatal.
If you are bitten or scratched by an animal:
- Wash the wound with soap and water right away for 10 minutes.
- Call your health care provider or local board of health. They can help you determine if you need to be treated for a rabies exposure.
- Call your local animal control officer as they may be able to catch the animal that scratched or bit you and advise you about quarantining domestic animals.
- Have wild animals tested immediately for rabies.
If your pet is bitten or scratched by another animal:
- Call your veterinarian to help you determine if the animal needs medical attention.
- If necessary, confine your animal and watch it to see if it develops signs of rabies. Your local animal control can help you determine if this is necessary.
- Learn more about pets and rabies on our website.
Prevention
- Enjoy wild animals from a distance.
- Keep your trash cans in a closed garage or shed.
- Don’t feed your pets outside.
- Report stray or sick animals to animal control. Do not try to deal with an animal who may be rabid yourself.
- Keep your pets’ vaccinations up to date.
- Maintain control of your pets when outdoors.
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WEST NILE VIRUS
West Nile Virus is a virus that causes encephalitis and is primarily transmitted to humans and other animals by mosquitoes and ticks while they feed. In recent years, mosquito collection and testing has provided the most reliable indication of current activity.
Transmission
- Mosquito bites (most common).
- Spread through blood transfusion or organ transplant.
- Direct contact with an infected person, bird, or animal will not spread the virus.
Symptoms
- Most people who become infected do not develop any symptoms.
- About 1 in 5 people who are infected will develop a fever and other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people exhibiting these symptoms recover completely, but fatigue and weakness can last for weeks or months.
- Less than 1% of people who are infected will develop a serious neurologic illness such as encephalitis or meningitis (inflammation of the brain or surrounding tissues). These symptoms include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis. People over 60 and those who have received organ transplants or who have certain medical conditions (cancer, diabetes, hypertension, or kidney disease) are at greater risk for serious illness.
Treatment
- No vaccine or specific antiviral treatments are available. People with mild infections usually recover on their own.
- Over-the-counter pain relievers can be used to reduce fever and relieve some symptoms.
- In severe cases, patients need to be hospitalized.
Prevention
- Use insect repellents when outdoors, especially during peak mosquito times (dusk to dawn)
- Repellents containing DEET, picaridin, IR3535, lemon eucalyptus oil, and para-menthane-diol products provide longer-lasting protection.
- Wear long sleeves, long pants, and socks when outdoors.
- Spraying clothes with repellent containing permethrin or another EPA-registered repellent will give extra protection, but don’t apply repellents containing permethrin directly to skin.
- Install or repair screens on windows and doors to keep mosquitoes outside.
- Help reduce the number of mosquitoes around your property by emptying standing water on a regular basis.
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EASTERN EQUINE ENCEPHALITIS
Eastern equine encephalitis (EEE) is a rare but serious disease caused by a virus identified in mosquitoes. Outbreaks of EEE usually occur in Massachusetts every 10-20 years and typically last 2-3 years.
Transmission
- Mosquitoes become infected when they bite infected birds.
- Infected mosquitoes bite humans and animals to spread the disease.
- Humans and several other types of mammals (particularly horses and llamas) can become infected, but do not spread disease.
Symptoms
- Usually appear 3 to 10 days after a bite from an infected mosquito.
- High fever (often 103º to 106ºF), stiff neck, headache, and lack of energy
- Inflammation and swelling of the brain (encephalitis) is the most dangerous and frequent serious complication.
- The disease worsens quickly and some patients may go into a coma within a week.
Treatment
- No known treatment.
- People who survive this disease will often be permanently disabled.
Prevention
- Avoid mosquito bites:
- Use insect repellents when you go outside, especially during peak mosquito times (dusk to dawn). Repellents containing DEET, picaridin, IR3535, and some oil of lemon eucalyptus and para-menthane-diol products provide longer-lasting protection.
- Wear long sleeves, long pants, and socks when outdoors.
- Spraying clothes with repellent containing permethrin or another EPA-registered repellent will give extra protection, but don’t apply repellents containing permethrin directly to skin.
- Install or repair screens on windows and doors to keep mosquitoes outside.
- Help reduce the number of mosquitoes around your property by emptying standing water on a regular basis.
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ZIKA VIRUS
Zika is a virus that is spread by the bite of an infected mosquito. Most people infected with Zika virus do not get sick, but the virus can sometimes be passed from a pregnant woman to a fetus which may cause a serious birth defect of the child’s brain. In February of 2016, the World Health Organization (WHO) declared Zika virus a Public Health Emergency of International Concern (PHEIC) and pregnant women were advised not to travel to certain infected countries.
Transmission
- Through the bite of an infected Aedes species mosquito. These mosquitoes also can spread chikungunya and dengue. They are aggressive daytime biters, but they can also bite at night.
- A pregnant woman already infected with Zika virus can pass the virus to her fetus during the pregnancy or around the time of birth.
- Zika virus can be spread by a man to sexual partners.
- Once a person has been infected, he or she is likely to be protected from future infections.
Symptoms
- Many people won’t have symptoms or will only have mild symptoms.
- Fever, rash, joint pain, conjunctivitis (red eyes), muscle pain, and headache.
The incubation period is not known, but is likely to be a few days to a week. The virus usually remains in the blood of an infected person for about a week but it can be found longer in some people.
Treatment
- People usually don’t get sick enough to go to the hospital. For this reason, many people might not realize they have been infected.
- There is currently no specific treatment for the virus, and the focus is typically on relief of the symptoms through rest, rehydration, and acetaminophen for fever and pain. (Aspirin and non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen should be avoided.)
Prevention
- Avoid mosquito bites:
- Use insect repellents when outdoors, especially during peak mosquito times (dusk to dawn). Repellents containing DEET, picaridin, IR3535, lemon eucalyptus oil, and para-menthane-diol products provide longer-lasting protection.
- Wear long sleeves, long pants, and socks when outdoors.
- Spraying clothes with repellent containing permethrin or another EPA-registered repellent will give extra protection, but don’t apply repellents containing permethrin directly to skin.
- Install or repair screens on windows and doors to keep mosquitoes outside.
- Help reduce the number of mosquitoes around your property by emptying standing water on a regular basis.
- Practice safe sex, as men can pass Zika to sexual partners.
- Avoid travel to countries where the Zika virus has been reported.
- No vaccine exists to prevent Zika.
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