Avian Caused Diseases and their Effects on Humans
Recently, avian diseases have posed a global problem. Many species of birds have been exposed to certain diseases that could easily spread to other birds because of migration. Unfortunately, these diseases are also transmittable to humans, posing an even bigger problem. Avian diseases have caused the death of many birds, and it could be as equally fatal to mankind. This research paper aims to discuss the avian diseases and their effects of humans when they are transmitted.
Animal diseases that are transmittable to humans are called zoonoses (Jacob, Gaskin, Wilson and Mather 1). The diseases may come from varied agents, such as protozoa, fungi, bacteria, Chlamydia or simply viruses. A person’s vulnerability to such diseases and the seriousness of the condition depend on one’s age, status of health and the immune system, as well as the reception of early treatment or therapy. The capacity of the agents to render an individual sick is also dependent on the “virulence of the organism, the dose to which the person is exposed, as well as route of infection” (Jacob et al. 1).
The four common types of avian infections transmittable to humans are “chlamydiosis, salmonellosis, colibacillosis and arizonosis” (Jacob et al. 1). The first two infections could be serious and deadly (Jacob et al. 1).
Chlamydiosis is caused by an organism called Chlamydia psittaci (Jacob et al. 1). This organism is present throughout the world and infects over 100 species of birds. The disease is called psittacosis or parrot fever, as it affects psittacine birds like parakeets and parrots. The disease is referred to as ornithosis when it is transmitted to humans. The disease is communicable when bird feces carry the organism and its dust is inhaled and carried by other birds. Because the organism can still infect in a dry state, it could be spread through clothes and bird-keeping equipment. Human to human transmission is possible through saliva (Jacob et al. 2). When a person is diagnosed with chlamydiosis, the patient appears to be suffering from a respiratory disease. The symptoms include pains in the chest, muscles and joint; as well as cough, headache and appetite loss. There are several complications, causing the enlargement of the spleen and the “inflammation of the heart” (Jacob et al. 2). Treatment for the disease includes the antibiotic called tetracycline (Jacob et al. 2).
Salmonellosis is caused by the Salmonella species which often affect persons with high stress levels (Jacob et al. 2). The symptoms for this disease are rather common: fever, vomiting and diarrhea. These could soon develop into weakness and dehydration. However, for those who are too young or too old, the disease may prove fatal. In serious cases, septicemia may occur along with headaches and again, spleen enlargement. Salmonellosis may also cause infections in organs such as the heart and kidney. Moreover, the organism Salmonella can affect humans through ingestion of contaminated food, like eggs that are not properly cooked. This is because the bacteria are usually food in the eggs. Treatment of Salmonellosis includes electrolytes and increased liquid intake. Antibiotics also play a part in Salmonellosis treatment (Jacob et al. 2).
Colibacillosis occurs because of the Escherichia coli bacteria, popularly known as E.coli (Jacob et al. 2). This kind of bacteria usually dwells in the animal’s intestines. Humans who have colibacillosis suffer from diarrhea. Dysentery, fever and shock are the identified complications of the disease (Jacob et al. 3). Generally, treatment of colibacillosis is symptomatic; it involves many fluids and other antidiarrheals. However, antibiotics are used in more serious cases (Jacob et al. 3).
Lastly, Arizonosis is derived from the Salmonella Arizona bacteria (Jacob et al. 3). Despite its name, the bacteria occur throughout the world. Like the aforementioned infections, humans with this kind of bacteria suffer from diarrhea. For those with weak immune systems, septicemia may occur as a complication. The handling of eggs is seen as the major cause of bacteria transmission. Antibiotics may be used to prevent death (Jacob et al. 3).
Aside from these diseases, there exists the avian influenza or more commonly referred to as bird flu (World Health Organization [WHO]). It is an alarming disease that affects poultry all over the world in a frequent rate (Europa). As the name suggests, this kind of influenza affects birds (WHO). However, pigs are also sometimes infected. Even though the viruses that cause avian influenza are specific when it comes to species, it still can be transmitted to and affect humans (WHO).
Avian influenza viruses are categorized into two forms, depending on how they affect poultry: “Highly Pathogenic Avian Influenza (HPAI) and Low Pathogenic Avian Influenza (LPAI)” (Europa). LPAI manifests relatively unnoticeable symptoms in birds, like a decrease in production of eggs and ruffling of feathers (WHO). HPAI has more severe symptoms and affects birds in a short amount of time. HPAI also causes fatality in birds (WHO).
Influenza viruses are distinguished as having three types: A, B and C (Europa). It is influenza A that affects birds, humans, and in rare cases, pigs and horses. In addition, Influenza A has “16 H subtypes and 9 N subtypes” (WHO). It was determined that the subtypes of H5 and H7 belong to the HPAI. Nonetheless, not every virus that falls under these subtypes is “highly pathogenic,” nor does it severely affect poultry (WHO). At present, it is established that H5 and H7 viruses first affect poultry as LPAI. However, the viruses evolve as it spreads, and in a short period of time, it becomes HPAI (WHO).
As for humans, there are four influenza virus subtypes which are known to affect humans: H1N1, H1N2, H3N2 and H7N2 (“General Information”). However, H5N1 is the one of the viruses which not only infects birds, but humans as well. H5N1 is detrimental to human health on two points (WHO). First, H5N1 could directly be transmitted from poultry to humans; in fact, it is responsible for most of the human deaths. This is because the disease affects the individual just as quickly as it causes deterioration and death. The symptoms of avian influenza usually begin with conjunctivitis or eye infections, and then proceeds to symptoms which resemble that of ordinary influenza: sore throat, cough, muscle pains and fever (Center for Disease Control and Prevention [CDC]). Eventually, the illness will progress into nausea and vomiting, multiple organ failure and viral pneumonia (CDC).
The second danger that H5N1 poses of humans is the possibility of the virus to mutate into a form which would be contagious from human to human (WHO). Such development would trigger a pandemic (WHO).
Humans become infected with avian influenza through exposure to materials and places which are contaminated with bird feces (WHO). Bird-keepers are especially at risk, as they are exposed to a possibly contaminated environment with bird droppings. Those who slaughter and sell sick birds are most likely to be infected, as well as those who eat the contaminated meat. Even the handling and cooking of food may cause an avian influenza infection. It is equally important to properly and fully cook eggs (WHO).
There are a number of avian caused diseases that affect humans and are detrimental to human health. At a time when diseases in animals can be transmitted to humans, people must be very carefully in dealing with birds. All necessary precautions must be taken to prevent the spread and evolution of diseases that seriously threat humanity.
Center for Disease Control and Prevention. Avian Influenza A Virus Infections of Humans. 15 Dec. 2007. Department of Health and Human Services. 20 April 2008 <http://www.cdc.gov/flu/avian/gen-info/avian-flu-humans.htm>.
Europa. Links between human and avian influenza. 20 April 2008 <http://ec.europa.eu/health/ph_threats/com/Influenza/influhome/avian_influenza_en.htm>.
Jacob, Jacqueline, Jack Gaskin, Henry Wilson and F. Ben Mather. “Avian Diseases Transmissible to Humans.” Institute of Food and Agricultural Sciences. University of Florida. 20 April 2008 <http://edis.ifas.ufl.edu/PS019>.
PandemicFlu.gov. “General Information.” 20 April 2008 <http://www.pandemicflu.gov/general/index.html>.
World Health Organization. Avian influenza frequently asked questions. 5 Dec. 2005. Epidemic and Pandemic Alert and Response (EPR). 20 April 2008 <http://www.who.int/csr/disease/avian_influenza/avian_faqs/en/#present>.