Zoonotic Diseases of Various Species

Part II

Neil Grove

University of North Carolina – Chapel Hill

Division of Laboratory Animal Medicine

Note: The images in this presentation are for non-profit, educational use only.

What We Will Cover Baylisascaris Rocky Mountain Spotted Fever Lyme Disease Avian Influenza Mycobacterium marinum

For each disease we will answer these questions: What is it?

How do I get it?

What are the symptoms?

What preventive measure can be taken?

Baylisascaris Infection – What is it? Baylisascaris, an intestinal

raccoon roundworm, can infect a variety of other animals, including humans. The worms develop to maturity in the raccoon intestine, where they produce millions of eggs that are passed in the feces. (1)

Baylisaccaris Infection – What is it? Released eggs take 2-4

weeks to become infective to other animals and humans.

The eggs are resistant to most environmental conditions and with adequate moisture, can survive for years.(1)

Baylisascaris Infection – What is it? Infected raccoons have been

found throughout the United States, mainly in the Midwest, Northeast, middle Atlantic, and West coast.

Infection rarely causes symptoms in raccoons. Predator animals, including dogs, may also become infected by eating a smaller animal that has been infected with Baylisascaris. (1)

How Do I get It? People become infected when they

accidentally ingest infective eggs in soil, water, or on objects that have been contaminated with raccoon feces.

When humans ingest these eggs, they hatch into larvae in the person's intestine and travel throughout the body, affecting the organs and muscles.(1)

Heightened Risk Anyone who is exposed to

environments where raccoons live is potentially at risk.

Young children or developmentally disabled persons are at highest risk for infection when they spend time outdoors and may put contaminated fingers, soil, or objects into their mouths. (1)

Heightened Risk Hunters, trappers,

taxidermists, and wildlife handlers may also be at increased risk if they have contact with raccoons or raccoon habitats.(1)

How Common is Human Infection? Infection is rarely diagnosed. Fever than 25 cases

have been diagnosed and reported in the United States as of 2003.

It is believed that cases are mistakenly diagnosed as other infections or go undiagnosed.

Cases have been reported in Oregon, California, Minnesota, Illinois, Michigan, New York, and Pennsylvania.

Five of the infected persons died.(1)

Symptoms Symptoms of infection depend on how many eggs

are ingested and where in the body the larvae migrate (travel to).

Once inside the body, eggs hatch into larvae and cause disease when they travel through the liver, brain, spinal cord, or other organs.

Ingesting a few eggs may cause few or no symptoms, while ingesting large numbers of eggs may lead to serious symptoms. Symptoms of infection may take a week or so to develop.(1)

Symptoms Symptoms include: Nausea Tiredness Liver enlargement Loss of coordination Lack of attention to people

and surroundings Loss of muscle control Coma Blindness (1)

Prevention Avoid direct contact with raccoons — especially their feces. Do not

keep, feed, or adopt raccoons as pets! Raccoons are wild animals. Discourage raccoons from living in and around your home or parks

by : preventing access to food closing off access to attics and basements keeping sand boxes covered at all times, (becomes a latrine) removing fish ponds — they eat the fish and drink the water eliminating all water sources removing bird feeders keeping trash containers tightly closed clearing brush so raccoons are not likely to make a den on your

property (1)

Prevention Stay away from areas and materials that might be

contaminated by raccoon feces. Raccoons typically defecate at the base of or in raised forks

of trees, or on raised horizontal surfaces such as fallen logs, stumps, or large rocks.

Raccoon feces also can be found on woodpiles, decks, rooftops, and in attics, garages, and haylofts.

Feces usually are dark and tubular, have a pungent odor (usually worse than dog or cat feces), and often contain undigested seeds or other food items. (1)

Prevention To eliminate eggs, raccoon feces and material

contaminated with raccoon feces should be removed carefully and burned, buried, or sent to a landfill.

Care should be taken to avoid contaminating hands and clothes.

Treat decks, patios, and other surfaces with boiling water or a propane flame-gun. (Exercise proper precautions!)(1)

Prevention Newly deposited eggs take at least 2-4

weeks to become infective. Prompt removal and destruction of raccoon feces will reduce risk for exposure and possible infection.

Contact your local animal control office for further assistance. (1)

Case Description In January 2000, a boy aged 17 years with an 8-year history of

severe developmental disabilities was admitted to a Los Angeles hospital comatose and with generalized hypertonia and hyperreflexia. His mouth was tightly clenched, his eyes wandered rapidly, and he responded only to painful stimuli. Two days before admission, he had a low-grade fever, drowsiness, and problems with coordination. Tests on CSF and blood failed to identify an infectious agent. On examination by a pathologist, a brain biopsy revealed sections of a nematode consistent with Baylisascaris species. The patient's condition deteriorated and he had progressive, deep white matter abnormalities of the brain on MRI. After a 2-month hospitalization, he was transferred to a long-term--care facility where he remained comatose until he died a year later. (2)

Case Description The patient had resided in a group home for

developmentally handicapped adolescents and adults in Los Angeles County. In February 2000, a field study conducted in the yard in which the patient regularly played revealed several sites containing raccoon feces; a sample of sandbox soil was positive for BP eggs. Multiple sites in the adjoining yard, to which he also had access, contained raccoon feces with BP eggs. (2)

Review Questions Released eggs take ________ to become

infective to other animals and humans.

Answer Released eggs take 2-4 weeks to become

infective to other animals and humans.

Question – True or False Human Baylisascaris infection is quite

common, with an average of one diagnosed case per week throughout the northeastern United States.

Answer False - Infection is rarely diagnosed. Fewer

than 25 cases have been diagnosed and reported in the United States as of 2003.

Rocky Mountain Spotted Fever – What is It? Rocky Mountain

spotted fever (RMSF) is the most severe tick-borne rickettsial illness in the United States. This disease is caused by infection with the bacterial organism Rickettsia rickettsii.(3) Gimenez stain of tick

hemolymph cells infected with R. rickettsii

Rocky Mountain Spotted Fever – What is It?

Rocky Mountain spotted fever has been a reportable disease in the United States since the 1920s.

In the last 50 years, approximately 250-1200 cases of Rocky Mountain spotted fever have been reported annually, although it is likely that many more cases go unreported. (3)

Annual incidence per million population for Rocky Mountain spotted fever by state in the United States for 2002, as determined on the basis of cases reported to the National Electronic Telecommunications System for Surveillance.

Rocky Mountain Spotted Fever – Where is It?

Over half of Rocky Mountain spotted fever infections are reported from the south-Atlantic region of the United States (Delaware, Maryland, Washington D.C., Virginia, West Virginia, North Carolina, South Carolina, Georgia, and Florida).

Infections also occur in The Pacific region (Washington, Oregon, and California) and west south-central (Arkansas, Louisiana, Oklahoma, and Texas) region. (3)

Rocky Mountain Spotted Fever – Where is It? The states with the highest incidences of Rocky

Mountain spotted fever are North Carolina and Oklahoma; these two states combined accounted for 35% of the total number of U.S. cases reported to CDC during 1993 through 1996.

Although Rocky Mountain spotted fever was first identified in the Rocky Mountain states, less than 3% of the U.S. cases were reported from that area during the same interval (1993-1996). (3)

How Do I Get It? The organism that causes Rocky Mountain

spotted fever is transmitted by the bite of an infected tick. Less commonly, infections may occur following exposure to crushed tick tissues, fluids, or tick feces.

In the case of Rocky Mountain spotted fever, ticks are the natural hosts, serving as both reservoirs and vectors of R. rickettsii. (3)

How Do I Get It? Because ticks on dogs can be infected with

R. rickettsii, dogs and people can get Rocky Mountain spotted fever from the same ticks. These ticks can also bite other animals and pass Rocky Mountain spotted fever to them. (3)

How Do I Get It? The American dog tick

(Dermacentor variabilis) and Rocky Mountain wood tick (Dermacentor andersoni) are the primary athropods (vectors) which transmit Rocky Mountain spotted fever bacteria in the United States. (3)

American Dog Tick

Rocky Mountain Wood Tick

How Do I Get It? The brown dog tick

Rhipicephalus sanguineus has also been implicated as a vector as well as the tick Amblyomma cajennense in countries south of the United States.(3)

How Do I Get It? Over 90% of patients with Rocky Mountain

spotted fever are infected during April through September.  This period is the season for increased numbers of adult and nymphal Dermacentor ticks.

A history of tick bite or exposure to tick-infested habitats is reported in approximately 60% of all cases of Rocky Mountain spotted fever.(3)

Symptoms Initial symptoms may

include fever, nausea, vomiting, severe headache, muscle pain, lack of appetite.

The rash first appears 2-5 days after the onset of fever and is often not present or may be very subtle when the patient is initially seen by a physician.(3)

Symptoms Younger patients usually

develop the rash earlier than older patients. Most often it begins as small, flat, pink, non-itchy spots (macules) on the wrists, forearms, and ankles. These spots turn pale when pressure is applied and eventually become raised on the skin.(3) Early (macular) rash on sole

of foot

Symptoms Later signs and symptoms

include rash, abdominal pain, joint pain, diarrhea.

The characteristic red, spotted (petechial) rash of Rocky Mountain spotted fever is usually not seen until the sixth day or later after onset of symptoms, and this type of rash occurs in only 35% to 60% of patients with Rocky Mountain spotted fever. (3)

Late (petechial) rash on palm and forearm

Symptoms The rash involves the

palms or soles in as many as 50% to 80% of patients; however, this distribution may not occur until later in the course of the disease. As many as 10% to 15% of patients may never develop a rash.(3)

Characteristic rash of late-stage Rocky Mountain spotted fever on legs of a patient

RMSF - Hospitalization Rocky Mountain spotted fever

can be a very severe illness and patients often require hospitalization.

Because R. rickettsii infects the cells lining blood vessels throughout the body, severe manifestations of this disease may involve the respiratory system, central nervous system, gastrointestinal system, or renal system. (3)

RMSF - Hospitalization Host factors associated with severe or fatal

Rocky Mountain spotted fever include advanced age, male sex, African-American race, chronic alcohol abuse, and glucose-6-phosphate dehydrogenase (G6PD) deficiency. (3)

RMSF - Hospitalization Deficiency of G6PD is a sex-linked genetic

condition which occurs with highest frequencies in people of African, Middle Eastern, and Southeast Asian origin; it affects approximately 12% of the U.S. African-American male population; deficiency of this enzyme is associated with a high proportion of severe cases of Rocky Mountain spotted fever.

This is a rare clinical course that is often fatal within 5 days of onset of illness. (3)

Long-Term Health Problems Long-term health problems following acute Rocky

Mountain spotted fever infection include partial paralysis of the lower extremities, gangrene requiring amputation of fingers, toes, or arms or legs, hearing loss, loss of bowel or bladder control, movement disorders, and language disorders.

These complications are most frequent in persons recovering from severe, life-threatening disease, often following lengthy hospitalizations.(3)

Prevention Limiting exposure to ticks reduces the likelihood

of infection with Rocky Mountain spotted fever. In persons exposed to tick-infested habitats,

prompt careful inspection and removal of crawling or attached ticks is an important method of preventing disease.

It may take extended attachment time before organisms are transmitted from the tick to the host.(3)

Prevention Wear light-colored clothing which allows you to see ticks that are

crawling on your clothing. Tuck your pants legs into your socks so that ticks cannot crawl up

the inside of your pants legs.

Apply repellents to discourage tick attachment. Repellents containing permethrin can be sprayed on boots and clothing, and will last for several days. Repellents containing DEET can be applied to the skin, but will last only a few hours before reapplication is necessary. Use DEET with caution on children.  Application of large amounts of DEET on children has been associated with adverse reactions. (3)

Prevention Conduct a body check upon return from potentially

tick-infested areas by searching your entire body for ticks. Use a hand-held or full-length mirror to view all parts of your body. Remove any tick you find on your body.

Parents should check their children for ticks, especially in the hair, when returning from potentially tick-infested areas.  Ticks may also be carried into the household on clothing and pets and attach later, so both should be examined carefully to exclude ticks. (3)

Review Questions _________ and_______; these two states

combined accounted for 35% of the total number of U.S. cases reported to CDC during 1993 through 1996.

Answer North Carolina and Oklahoma

Question The __________ and Rocky Mountain

wood tick are the primary athropods (vectors) which transmit Rocky Mountain spotted fever bacteria in the United States.

Answer American Dog Tick

Question Over 90% of patients with Rocky Mountain

spotted fever are infected between the months of _______ and ________.

Answer April and September

Lyme Disease – What is it? Lyme disease is

caused by the bacterium Borrelia burgdorferi

Borrelia burgdorferi

How Do I Get It? The Lyme disease

bacterium, Borrelia burgdorferi, normally lives in mice, squirrels and other small animals. It is transmitted among these animals – and to humans -- through the bites of certain species of ticks. (4)

Symptoms Within 1 to 2 weeks of

being infected, people may have a "bull's-eye" rash with fever, headache, and muscle or joint pain. Some people have Lyme disease and do not have any early symptoms. Other people have a fever and other "flu-like" symptoms without a rash. (4)

“Bull’s-eye” Rash

Symptoms After several days or weeks, the bacteria

may spread throughout the body of an infected person. These people can get symptoms such as rashes in other parts of the body, pain that seems to move from joint to joint, and signs of inflammation of the heart or nerves. (4)

Symptoms If the disease is not treated, a few patients

can get additional symptoms, such as swelling and pain in major joints or mental changes, months after getting infected.(4)

Prevention Whenever possible, you should avoid entering areas that are

likely to be infested with ticks, particularly in spring and summer when nymphal ticks feed.

If you are in an area with ticks, you should wear light-colored clothing so that ticks can be spotted more easily and removed before becoming attached.

If you are in an area with ticks, wear long-sleeved shirts, and tuck your pants into socks. You may also want to wear high rubber boots (since ticks are usually located close to the ground). (4)

Prevention Application of insect repellents containing

DEET (n,n-diethyl-m-toluamide) to clothes and exposed skin, and permethrin (which kills ticks on contact) to clothes, should also help reduce the risk of tick attachment. DEET can be used safely on children and adults but should be applied according to Environmental Protection Agency guidelines to reduce the possibility of toxicity. (4)

Prevention Since transmission of B. burgdorferi from an

infected tick is unlikely to occur before 36 hours of tick attachment, check for ticks daily and remove them promptly. Embedded ticks should be removed by using fine-tipped tweezers. Cleanse the area with an antiseptic.

You can reduce the number of ticks around your home by removing leaf litter, and brush- and wood-piles around your house and at the edge of your yard. By clearing trees and brush in your yard, you can reduce the likelihood that deer, rodents, and ticks will live there(4)

Question Being bitten by a _____ is the most

common cause of Lyme disease.

Answer tick

Question To repel ticks, insect repellents should

contain ______.

Answer Deet

Avian Influenza – What is it? Avian influenza, or “bird

flu”, is a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs.

Avian influenza viruses are highly species-specific, but have, on rare occasions, crossed the species barrier to infect humans.(7)

Avian Influenza – What is it? Influenza A (H5N1) is an influenza A virus

subtype that occurs mainly in birds, is highly contagious among birds, and can be deadly to them. Outbreaks of H5N1 among poultry are ongoing in a number of countries. (6)

H5N1 is associated with human illness.

Avian Influenza – What is it? Influenza viruses are grouped into three types,

designated A, B, and C. Influenza A and B viruses are of concern for human health. Only influenza A viruses can cause pandemics (worldwide outbreaks).(7)

While H5N1 does not usually infect people, human cases of H5N1 infection associated with these outbreaks have been reported.(6)

Avian Influenza – What is it? Wild waterfowl are

considered the natural reservoir of all influenza A viruses.

Considerable circumstantial evidence suggests that migratory birds can introduce low pathogenic H5 and H7 viruses to poultry flocks, which then mutate to the highly pathogenic form.(7)

Avian Influenza – What is it? Of the few avian influenza viruses that have crossed the

species barrier to infect humans, H5N1 has caused the largest number of cases of severe disease and death in humans.

Unlike normal seasonal influenza, where infection causes only mild respiratory symptoms in most people, the disease caused by H5N1 follows an unusually aggressive clinical course, with rapid deterioration and high fatality.

Primary viral pneumonia and multi-organ failure are common. In the present outbreak, more than half of those infected with the virus have died. Most cases have occurred in previously healthy children and young adults.(7)

Avian Influenza – What is it? A second risk, of even greater concern, is

that the virus – if given enough opportunities – will change into a form that is highly infectious for humans and spreads easily from person to person. Such a change could mark the start of a global outbreak (a pandemic).(7)

How do I get it? Direct contact with infected

poultry, or surfaces and objects contaminated by their feces, is presently considered the main route of human infection.

To date, most human cases have occurred in rural or periurban areas where many households keep small poultry flocks, which often roam freely, sometimes entering homes or sharing outdoor areas where children play. (7)

How do I get it? As infected birds shed large quantities of

virus in their feces, opportunities for exposure to infected droppings or to environments contaminated by the virus are abundant under such conditions. (7)

How do I get it? Because many households in Asia depend

on poultry for income and food, many families sell or slaughter and consume birds when signs of illness appear in a flock, and this practice has proved difficult to change.

Exposure is considered most likely during slaughter, defeathering, butchering, and preparation of poultry for cooking.(7)

How do I get it? Because all influenza viruses have the

ability to change, scientists are concerned that H5N1 virus one day could be able to infect humans and spread easily from one person to another. (6)

How do I get it? Because these viruses do not

commonly infect humans, there is little or no immune protection against them in the human population.

If these H5N1 viruses gain the ability for efficient and sustained transmission among humans, an influenza pandemic (world wide) could result, with potentially high rates of illness and death. (6)

How do I get it? It is likely that H5N1 infection among birds

has become endemic in certain areas and that human infections resulting from direct contact with infected poultry will continue to occur. (6)

Does the virus spread easily from birds to humans?

No. Though more than 100 human cases have occurred in the current outbreak, this is a small number compared with the huge number of birds affected and the numerous associated opportunities for human exposure, especially in areas where backyard flocks are common.

It is not presently understood why some people, and not others, become infected following similar exposures.(7)

Since January, 2004 WHO has reported human cases of avian influenza A (H5N1) in the following countries:

East Asia and the Pacific:

Cambodia China Indonesia Thailand Vietnam

Europe & Eurasia: Azerbaijan Turkey

Near East: Egypt Iraq

Symptoms The reported symptoms of avian influenza

in humans have ranged from typical influenza-like symptoms (e.g., fever, cough, sore throat, and muscle aches) to eye infections (conjunctivitis), pneumonia, acute respiratory distress, viral pneumonia, and other severe and life-threatening complications. (6)

Symptoms The majority of known human H5N1 cases

have begun with respiratory symptoms. However, one atypical fatal case of encephalitis in a child in southern Vietnam in 2004 was identified retrospectively as H5N1 influenza through testing of cerebrospinal fluid, fecal matter, and throat and serum samples. (6)

What precautions can be taken to reduce the risk for infection from wild birds in the United States?

As a general rule, the public should observe wildlife, including wild birds, from a distance. This protects you from possible exposure to pathogens and minimizes disturbance to the animal.

Avoid touching wildlife. If there is contact with wildlife do not rub eyes, eat, drink, or smoke before washing hands with soap and water.

Do not pick up diseased or dead wildlife. Contact your state, tribal, or federal natural resource agency if a sick or dead animal is found.(6)

What precautions can hunters take to reduce the risk for infection when hunting birds in the United States?

Hunters should follow routine precautions when handling game, including wild birds. The National Wildlife Health Center recommends that hunters:

Do not handle or eat sick game. Wear rubber or disposable latex gloves while handling and

cleaning game, wash hands with soap and water (or with alcohol-based hand products if the hands are not visibly soiled), and thoroughly clean knives, equipment and surfaces that come in contact with game.

Do not eat, drink, or smoke while handling animals. Cook all game thoroughly. (6)

Precautions There is currently a ban on the importation

of birds and bird products from H5N1-affected countries. The regulation states that no person may import or attempt to import any birds whether dead or alive, or any products derived from birds. (6)

Question 1 ____ and ____ influenza viruses are of

concern for human disease.

Answer A and B

Question 2 What does “pandemic” outbreak mean?

Answer global

Question 3 True or False – The H5N1 virus spreads

easily from birds to humans.

Answer False

Mycobacterium marinum – what is it? Mycobacterium marinum (M.

marinum) is a slowly growing bacteria that may cause disease in fish and people. The bacteria is normally found in bodies of fresh or salt water in many parts of the world.

Skin infection with Mycobacterium marinum is relatively rare and is usually acquired from swimming pools, aquariums, or fish-handling. This bacteria does not grow at normal body temperature. That is why it remains localized to the cooler skin surface. (8)

How do I get it? Human infections with M.

marinum under normal circumstances are rare. However, people who have breaks in the skin such as cuts and scrapes are at increased risk:

When in contact with water from an aquarium or fish tank

When handling, cleaning, or processing fish, or

While swimming or working in fresh or salt water.

M. marinum infection is not spread from person to person.

What are the Symptoms? When M. marinum infects the skin, it

causes localized microscopic nodules to form. These nodules are called granulomas. They occur at sites of skin trauma where there are scratches, cuts, and the like.(8)

What are the Symptoms? The most frequent sign is

a slowly developing nodule (raised bump) at the site the bacteria entered the body. Frequently, the nodule is on the hand or upper arm.

Later the nodule can become an enlarging sore (an ulcer). Swelling of nearby lymph nodes occurs. (8)

What are the Symptoms? Multiple granulomas may form in a line

along the lymphatic vessel that drains the site.  These lesions will usually spontaneously heal in several months.

This infection can also involve the joints (septic arthritis) and bones.(8)

Symptoms The granulomas usually appear within 2-3 weeks

of exposure. Some reported cases have developed 2 to 4 months or more after exposure to M. marinum because of the very slow-growing nature of this bacterium. 

A health care provider should be consulted if a skin nodule or reddened sore (ulcer) develops following direct skin contact with fresh or salt water or after handling or processing fish.(8)

Heightened Risk For people with compromise of the immune

system, M. marinum infection can be especially serious and involve disseminated (widespread) disease. If an infection is suspected under such circumstances, a health care provider should be promptly consulted.(8)

Prevention/Precautions Avoid fresh or salt water

activities if there are open cuts, scrapes, or sores on your skin, especially in bodies of water where this bacterium is known to exist.

If you have a weakened immune system, you can reduce the risk of infection by carefully covering cuts, scrapes, or sores during fresh or salt water activities and while cleaning fish tanks or handling, cleaning or processing fish.(8)

Prevention/Precautions Wear heavy gloves (leather or heavy cotton) while cleaning

or processing fish, especially fish with sharp spines that may cause cuts, scratches, or sores to the hands and skin. Wash hands thoroughly with soap and water after fish processing or use a waterless cleanser.

Wear waterproof gloves while cleaning home aquariums or fish tanks. Wash hands and forearms thoroughly with soap and running water after cleaning the tank, even if gloves were worn.

Ensure regular and adequate chlorination of swimming pools to kill any bacteria that may be present. (8)

References

1. CDC. Baylisascaris Infection Fact Sheet.

http://www.cdc.gov/ncidod/dpd/parasites/baylisascaris/factsht_baylisascaris.htm 2. CDC. Morbidity and Mortality Monthly Report. Raccoon Roundworm Encephalitis --- Chicago,

Illinois, and Los Angeles, California, 2000. January 4, 2002 / 50(51);1153-5 3. CDC. Rocky Mountain Spotted Fever Home. http://www.cdc.gov/ncidod/dvrd/rmsf/index.htm 4. CDC. Lyme Disease and Animals. http://www.cdc.gov/healthypets/diseases/lyme.htm 5. CDC. Avian Influenza Infection in Humans. http://www.cdc.gov/flu/avian/gen-info/avian-flu-

humans.htm 6. CDC. Key Facts About Avian Influenza (Bird Flu) and Avian Influenza A (H5N1) Virus

http://www.cdc.gov/flu/avian/gen-info/facts.htm 7. WHO. Avian influenza frequently asked questions

http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/index.html 8. MedicineNet.com. Mycobacterium marinum.

http://www.medicinenet.com/mycobacterium_marinum/article.htm

Disclaimer This presetation was created while I was an

employee of Priority One Services (POS) at the National Institute of Environmental Health Sciences (NIEHS). Thus, both organizations deserve credit for supporting the work.

However, the opinions expressed in this presentation are mine and don’t necessarily reflect those of POS, NIEHS, or UNC DLAM.