Weekend Economists Debate: Which Came First? The Incredible, Edible Egg November 27-29, 2015

[Demeter]

12. FOWL DISEASES AND HUMAN-BIRD TRANSMISSION

Many diseases that afflict humans have jumped from other species, and chickens are no different.

CHICKENPOX --not traced to chickens--Chickens don't even get infected by the virus — varicella zoster, a member of the herpes family — that causes the rash. (They can however, get an infection with similar effects called fowl pox.)

In the 1600s, an English physician named Richard Morton described what he thought a mild form of smallpox as "chicken pox." Later, in 1767, a physician named William Heberden, also from England, was the first physician to clearly demonstrate that chickenpox was different from smallpox.

http://www.newworldencyclopedia.org/entry/Chickenpox

There are many explanations offered for the origin of the name "chickenpox:"

Samuel Johnson suggested that the disease was "no very great danger," thus a "chicken" version of the pox;
the specks that appear looked as though the skin was pecked by chickens;
the disease was named after chick peas, from a supposed similarity in size of the seed to the lesions;
the term reflects a corruption of the Old English word giccin, which meant "itching."

As "pox" also means curse, in medieval times some believed it was a plague brought on to curse children by the use of black magic.

Before the 1995 introduction of the varicella vaccine, Varivax, virtually all children born each year in the United States contracted chickenpox, with a rate of only about five of every 1,000 needing hospitalization and about 100 deaths a year (Longe 2006). By ages nine or ten, about 80 to 90 percent of American children were infected, and adults counted for less than five percent of all cases, with about 90 percent immune to the virus (Longe 2005). However, adults are more likely than children to suffer dangerous consequences, and about half of all deaths occur among adults (Knapp and Wilson 2005).

Humans are the only known animal that the disease affects naturally. However, chickenpox has been caused in other primates, including chimpanzees and gorillas.

I MYSELF BEAR A SCAR FROM CHICKEN POX, AND MY CHILDREN HAD IT, BUT IT WILL BE UNKNOWN TO FUTURE GENERATIONS, BARRING A COMPLETE COLLAPSE OF PUBLIC HEALTH. IT IS SAID ADULTS HAVE A 1/5 CHANCE OF SHINGLES, WHICH IS A SECONDARY MANIFESTATION IN A MUCH MORE SERIOUS FORM...HENCE THE PROMOTION OF SHINGLES VACCINE FOR ADULTS.

Avian Influenza

Avian influenza refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Avian flu viruses do not normally infect humans. However, sporadic human infections with avian flu viruses have occurred.

Avian Influenza A Virus Infections in Humans

Although avian influenza A viruses usually do not infect humans, rare cases of human infection with these viruses have been reported. Most human infections with avian influenza A viruses have occurred following direct or close contact with infected poultry. Illness in humans has ranged from mild to severe.

The spread of avian influenza A viruses from one ill person to another has been reported very rarely, and has been limited, inefficient and not sustained. However, because of the possibility that avian influenza A viruses could change and gain the ability to spread easily between people, monitoring for human infection and person-to-person transmission is extremely important for public health.

Signs and Symptoms of Avian Influenza A Virus Infections in Humans

The reported signs and symptoms of low pathogenic avian influenza* (LPAI) A virus infections in humans have ranged from conjunctivitis to influenza-like illness (e.g., fever, cough, sore throat, muscle aches) to lower respiratory disease (pneumonia) requiring hospitalization. Highly pathogenic avian influenza (HPAI) A virus infections in people have been associated with a wide range of illness from conjunctivitis only, to influenza-like illness, to severe respiratory illness (e.g. shortness of breath, difficulty breathing, pneumonia, acute respiratory distress, viral pneumonia, respiratory failure) with multi-organ disease, sometimes accompanied by nausea, abdominal pain, diarrhea, vomiting and sometimes neurologic changes (altered mental status, seizures). LPAI H7N9 and HPAI Asian H5N1 have been responsible for most human illness worldwide to date, including the most serious illnesses and deaths.

Detecting Avian Influenza A Virus Infection in Humans

Avian influenza A virus infection in humans cannot be diagnosed by clinical signs and symptoms alone; laboratory testing is required. Avian influenza A virus infection is usually diagnosed by collecting a swab from the nose or throat of the sick person during the first few days of illness. This specimen is sent to a lab; the laboratory looks for avian influenza A virus either by using a molecular test, by trying to grow the virus, or both. (Growing avian influenza A viruses should only be done in laboratories with high levels of protection).

For critically ill patients, collection and testing of lower respiratory tract specimens may lead to diagnosis of avian influenza virus infection. For some patients who are no longer very sick or who have fully recovered, it may be difficult to find the avian influenza A virus in the specimen, using these methods. Sometimes it may still be possible to diagnose avian influenza A virus infection by looking for evidence of the body's immune response to the virus infection by detecting specific antibodies the body has produced in response to the virus. This is not always an option because it requires two blood specimens (one taken during the first week of illness and another taken 3-4 weeks later). Also, it can take several weeks to verify the results, and testing must be performed in a special laboratory, such as at CDC.

http://www.cdc.gov/flu/avianflu/avian-in-humans.htm

Chlamydiosis (Psittacosis)

Chlamydiosis (Psittacosis) is caused by Chlamydia psittaci, an obligate intracellular bacterial parasite. The disease in Psittacines (parrots) and humans is called psittacosis, while Ornithosis is the name of the disease in bird species other than Psittacines. The disease in psittacines is also commonly called Parrot Fever.

C. psittaci can cause disease in humans, birds, cows, goats, sheep and pigs. Most human cases are contracted from psittacines, pigeons, and turkeys. The disease can be transmitted from person to person.

A great variation in pathogenicity (the ability to cause disease) of various strains exists for humans and birds. Some strains - such as those found in pigeons - may not cause disease in their hosts. Other strains - especially those in psittacines can cause disease in people and birds.

Infected birds shed elementary bodies in their feces, urine, saliva, ocular secretions, nasal exudates, and feather dust. These infectious particles are inhaled or ingested by other birds and people. Egg transmission has been documented in the duck, budgie, and turkey. The incubation period in birds is several months to several years.

Birds with active chlamydiosis may have inflamed eyes, difficulty in breathing, watery droppings and green urates. Many birds are asymptomatic carriers and appear clinically normal yet infected. Any stress such as transportation, malnutrition, concurrent illness, poor ventilation, overcrowding, and breeding can cause shedding of the organism and clinical disease.

Humans are usually infected by the inhalation of infective particles in the air. The incubation period is 5 to 14 days. Symptoms are generally those of the flu - fever, diarrhea, chills, congunctivitis, and sore throat.

A number of tests are available to diagnose the disease in the live bird. Unfortunately, it is not possible to declare a bird free of chlamydia on the basis of any one test. It is recommended that an antigen and an antibody test be done. The new PCR (polymerase - chain reaction) is a highly sensitive test that is now available.

Treatment for both people and birds is doxycycline or tetracycline. People are treated for 3 weeks, while birds are treated for 45 days.

Salmonella

Salmonella is a gram negative aerobic rod-shaped bacterium that can infect people, birds, and other animals. It can persist in soil and water for long periods of time.

A large number of serotypes exist and the ability to cause disease depends upon the serotype involved. All salmonella serotypes produce endotoxins capable of causing food poisoning. The toxin in the food source and the bacterium are both capable of producing disease.

Birds can become infected with salmonella by oral ingestion of contaminated food, water and through the egg - either by ventical transmisson or by penetration of the egg shell. Poultry and pigeons may carry salmonella yet appear healthy. Infected birds will be lethargic, lose their appetite, have watery droppings and may develop arthritis. Parrots may develop bloody diarrhea, profound depression, a high white blood cell count, and often die.

Most human cases of salmonella are acquired by eating contaminated food especially poultry rather than from pet birds. The incubation period is 6 - 72 hours in people. Vomiting, bloody diarrhea, fever and dehydration may occur. Recovery may occur in 2 - 4 days. Salmonella can be transmitted from person to person. Humans carrying salmonella can infect their pet birds.

Diagnosis in the live bird can be difficult since birds may be intermittent shedders. Fecal or cloacal cultures are used for diagnosis. Birds are treated with aggressive antibiotics for 3 - 5 weeks based on culture and sensitivity. Birds may remain carriers for life.

Antibiotics are not usually prescribed for people unless they have a prolonged fever and are septicemic.

Avian Tuberculosis (Mycobacteriosis)

Avian Tuberculosis occurs throughout the world and has been found in the waterfowl, turkeys, psittacines, passerines, columbiformes and raptors.

In psittacines, tuberculosis is usually caused by Mycobacterium avium, Mycobacterium intracellulare and Mycobacterium genovense. M. tuberculosis and M. bovis have occassionally been isolated in birds. Humans are more commonly infected with M. tuberculosis and occasionally M. bovis. It is believed that immunocompetent humans are resisitant to the strains of tuberculosis found in birds, but that immunocompromised people - such as those infected with HIV, those on chemotherapy, the elderly and children are at increased risk.

Avian tuberculosis is transmitted by ingestion and inhalation of aerosolized infectious organisms from feces. Incubation in birds is weeks to months. Although many species of birds can be infected, the majority of cases occur in older amazons and grey cheeks. M.avium, the most common cause of tuberculosis in birds is often found in soil and water. It can survive for a long period of time in the environment and can multiply in inanimate objects.

Three types of syndromes may occur in birds. The classic form is that of tubercles or granulomas in many organs. A second form is the paratuberculosis form with lesions in the intestional tract. This is often seen in amazons, pionus, and Brotogeris parrots. With this form, high numbers of organisms are shed in the feces. A third form is a nontuberculous form or atypical form that is very difficult to recognize. This form commonly occurs in finches, canaries, and small pisttacines. The liver is usually very enlarged and large numbers of mycobacteria are found in cytology and histopathology.

Birds with the intestional form often present with chronic wasting disease - and Proventricular Dilitation Syndrome is often one of the suspected possible diseases. In addition to weight loss, depression, diarrhea, increased urination (polyuria), abdominal distention, lameness and difficulty in breathing may be present.

In adult humans, tuberculosis frequently affects the lungs, producing respiratory signs. In young children, the cervical lymph nodes are often involved, while immunocompromised people often have the disseminated form.

Diagnosis of tuberculosis in the live bird can be very difficult due to intermittent fecal shedding and obscure signs. Physical findings, very elevated white blood cell and low red blood cell count and other diagnostic tests which include radiology (x-rays), endoscopy and identification of acid fast bacteria in feces or tissues can lead to a preliminary diagnosis. Definitive diagnosis is based on culturing the organism from the feces or from an organ. Not all acid fast organisms are mycobacteria, therefore just identifying acid fast organisms does not provide a conclusive diagnosis. New tests that may aid in the diagnosis include the DNA probe and the polymerase chain test.

Erradication is difficult due to the chronic carrier state and intermittent shedding of a large number of organisms.

If a positive bird is identified, it should be separated from the collection. Treatment of a positive bird is contaversial because of the large number of organisms shed in the feces and because the organism is resistant to many of the drugs used to treat human T.B. The infected bird must be treated for a long period using combination drug treatment.

All contact birds should be quarantined for 2 years and tested at 6-12 week intervals.

People who are infected with human tuberculosis should not own birds, since these people may serve as a source of infection for their pet birds.

Avian Influenza

Influenza is caused by an enveloped RNA virus. It is an infectious disease of birds, swine, humans and other animals. Three types of Influenza viruses exist - types A, B, and C. Influenza A viruses infect birds and other animals, while B and C infect people.

Hundreds of subtypes of Influenza A viruses have been isolated from birds and other mammals. Influenza viruses are continuously undergoing change, resulting in new serotypes. Migratory birds, especially waterfowl are believed to be reservoirs for Influenza A virus. The infection often causes an inapparent intestinal disease in waterfowl. These infected waterfowl don't show signs of disease unless severely stressed by other diseases or transport. These inapparently infected birds shed the virus from their respiratory tract, conjunctiva (lining of the eyes) and in their feces - serving as a source of infection for other birds. Incubation may be as short as a few hours.

The signs of illness depend upon the species infected, the age, environmental factors, and virulence of the viral strain. Birds may die suddenly without showing signs of illness or develop depression, appetite loss, coughing, sneezing and decreased egg production.

Influenza A has been isotated from captive birds, including psittacines (parrots) and passerines (canaries, finches, sparrow, starlings, etc). Psittacines my demonstrate loss of balance, torticollis (twisted neck) and may die.

The virus may be isolated from swabs of the cloaca and upper respiratory tract in the live bird. It may be isolated from the lungs, liver, spleen and brain at postmortem.

A companion bird could serve as a source of virus exposure for humans, but it is more likely that humans could serve as a source of virus exposure for susceptible companion birds. If a human has clinical signs of the "flu", he should avoid contact with his bird.

Wild migratory birds should not be allowed contact with companion birds, chickens and turkeys - as they may serve as a means of spreading Influenza.

http://www.birdsnways.com/wisdom/ww1.htm

SO FAR, WE ARE SAFE FROM CHICKENS, EXCEPT FOR INFLUENZA WHEN PIGS ARE AROUND...AND SALMONELLA AND E. COLI