Tularemia Essays

Tularemia Essays Tularemia Essay Tularemia Essay Name: Course: Lecturer: Date: Tularemia Introduction Tularemia is a highly infectious disease, which affects humans and animals, caused by the bacterium francisella tularensis. The disease affects humans through various means such as skin contact with the infected animal, taking contaminated water, inhaling contaminated dust and aerosols, bites from ticks such as dog ticks, lone star ticks, and wood ticks, bites from deer flies, exposure in the laboratory, and as an act of bioterrorism (CDC). The bacterium is highly contagious, and a small number can cause the disease. terrorists can use it as a weapon, in form of inhalation, and this would increase the number of people susceptible to the disease. Pneumonic tularemia tends to be more severe. The disease causes severe pain and it could be fatal. Mosquitoes also carry the disease, and they can spread them to humans. The bacteria enter the human body through the skin, mouth, eyes, lungs, or throat. About one hundred animal species can carry the infection (Siderovski 12). This is in additi on to birds, arthropods, and fish, which can also carry the disease. Animals such as rabbits, hares, cats, muskrats, and rodents are more likely to get the infection. In cases of outbreak, the animals die in large numbers. There are no known cases of person-to-person infections. Farmers and hunters are at high risks of getting infections. Description and Classification Francisella tularensis is a gram-negative non-molatile bacterium with two biotypes, tularensis (biotype A) and palaearctica (biotype B). It is in capsule form with pleomorphic cells, which appear as short rods. It is an intracellular pathogen, able to live in ticks for a long time. the bacterium can survive in cool conditions for a long time but the cells are sensitive to heat. The bacterium can survive in water, as well as dry land. It also survives in soil, hay, decaying animal carcasses, and straw. Biotype A is limited to North America and it is highly virulent. Biotype B is found in North America, Europe, Asia and Americas, and it is less virulent. There are four known subspecies, and they include tularensis, holarctica, mediasiatica, and novicida. mediasiatica and novicida have low virulence subspecies tularensis is exclusive to north America, while subspecies holartica is present in Europe and north America (Suckow et al., 341). Signs and Symptoms The symptoms of the disease are varied, and they depend on the mode of infection, although all humans affected by the disease experience a high fever. A person infected with the disease normally experiences the symptoms after a period of 3-5 days, although the symptoms can range from 1-21 days. Other than fever, other symptoms include chills, headaches, muscle pain, eye irritation, sweating, diarrhea, dry coughs, weakness, and joint aches among others (CDC). A person with the infection develops a lesion at the site of entry of the bacteria. The sore is often red, with a ribbed rim and a punched-out center (Siderovski 36). The person develops inflammation of the lymph nodes in the affected area (Suckow et al 342). When the bacterium enters the bloodstream, it causes bacteremia, and this enables the infection to spread to other body organs such as kidneys, spleen, and liver (Siderovski 36). Animals infected with the disease often die, but they exhibit symptoms such as depression and an orexia (Suckow et al 342) Forms of Tularemia Some of the main forms of the disease include glandular, ocuglandular, oropharyngeal, ulceroglandular, and pneumonic. The bacteria in the ulceroglandular form of disease spreads to the lymph nodes at the point of entry. The ulceroglandular form of the disease is the most common. It occurs when the bacterium affects the person through the skin. A person with ulceroglandular develops a lesion, which develops into an ulcer. The ulcer heals after one week, and it is relatively painless (Oyston 921-930). The location of the ulcer in the body can help to determine the mode of transmission. Ulcers on the upper extremities on the body indicate that the person was in close contact with an infected animal. Ulcers on the lower extremities, abdomen or the back of the body indicate that the person got the infection from arthropods (Goddard 106). Glandular tularemia is similar to ulceroglandular, expect that the infected person does not develop an ulcer. The eye is a possible route of infection, and when this happens, the person develops ocuglandular tularemia. A person with this form of disease has swollen eyelids, and he or she develops conjunctivitis. Oropharyngeal tularemia develops when a person eats infected meat or drinks contaminated water (Oyston 921-930). It can also develop when a person puts infected fingers in the mouth (Siderovski 41). This form is also known as gastrointestinal tularemia. A person with this form of disease develops pharyngitis, swollen cervical lymph nodes, and ulcers. Diarrhea is a common symptom in this form of disease, and it ranges from mild and persistent diarrhea to acute diarrhea, which is often fatal. The infected person develops an ulceration of the bowel. He or she experiences nausea and vomiting. A person develops pneumonic or respiratory diarrhea through inhalation. A person with this form of the disease becomes delirious. He or she develops a non-productive cough, chest pain, and dyspenea. The bacteria replicates quickly once a person inhales it. The person might require assistance in breathing. Testing and Diagnosis Tularemia is a rare disease, and doctors find it hard to diagnose the disease. This is because the disease symptoms resemble symptoms of other diseases. Doctors look for symptoms such as swelling lymph nodes and ulcers on the skin to make their diagnosis (Siderovski 48). The patient can help the doctor, by pointing out any chance of exposure with an infected animal. Physicians can identify the disease by examining secretions and biopsy specimen using gram stain or direct fluorescent antibody. Examination using the fluorescent antibodies is quick, and the physician gets the report after a few hours but it is not always possible to guarantee the accuracy of the results (Dennis et al 2763-2773). When testing for the disease, it is important to alert those working in the laboratory, so that they can take the correct preventive measures. There have been several cases of people getting infections because of laboratory exposure. The most efficient way of confirming the disease is by growing it in culture, although it is often difficult to do so. One can grow culture using sputum or pharyngeal washing. For a person with inhalation tularemia, the physician grows the culture from fasting gastric aspirates. The culture has to contain cysteine, and the physician places it in an environment rich in carbon dioxide. It takes about four to six days for the culture to grow (Hepburn Simpson 231-240) Prevention and Treatment People can minimize their chances of infection by adopting several measures such as not handling carcasses since one does not know whether the animal had the diseases, and using gloves when handling infected animals and carcasses. People should not take water if they are not sure of its safety. Contaminated water is one of the easiest ways of acquiring the disease. People who take wild meat should ensure that they cook it thoroughly. Tularemia often affects wild animals, and people should be careful when consuming such meat. People in endemic areas should use repellants to get rid of arthropods, and reduce their chances of infection. They should treat their clothes with repellants, as this will help them to avoid insect bites. Worry about terrorists using the bacterium as a possible weapon has compelled researchers to develop a vaccine. There have been several attempts at this, and the live vaccine strain (LVS) seems to have been the most successful. The vaccine is successful in prov iding protection against small doses of a virulent strain. Governments have not licensed the vaccine because of its reversion to virulence, variable immunogenicity, and mixed colony morphology (Oyston 921-930). The disease can be fatal in humans, if not treated. The mortality rate for untreated tularemia is 30%. Treating the disease reduces this rate to 1% (Goddard 106). Doctors use antibiotics to treat the disease in human beings. Doctors use antibiotics such as streptomycin, gentamicin, doxycycline, and ciprofloxacin to treat the disease (CDC). These are the most common antibiotics, although other antibiotics such as tetracycline and chloramphenicol are in use (Goddard 106). Treatment depends on the type of medication used and stage of the disease, though it takes 10-21 days. The use of antibiotics has increased the chances of the patients’ recovery, and most patients treated usually recover from their illness. : CDC. Tularemia. Centers for Disease Control and Prevention. 2011. Web. 12 July 2012 Dennis, T. David et al. â€Å"Tularemia as a Biological Weapon.† The Journal of American Medical Association 285.21 (2001): 2763-2773 Goddard, Jerome. Infectious Diseases and Arthropods. New York, NY: Springer, 2008. Print Hepburn, J. Matthew and JH Simpson. Tularemia: Current Diagnosis and Treatment Options. 2008. Web. 12 July 2012 Oyston, C. F. Petra. â€Å"Francisella Tularensis: Unravelling the Secrets of an Intracellular Pathogen.† Journal of Medical Microbiology 57.8 (2008): 921-930. Print Siderovski, H. Susan. Tularemia. Infobase Publishing, 2006. Print Suckow, A, Mark et al. The Laboratory Rabbit, Guinea Pig, Hamster, and Other Rodents. Waltham, MA: Academic Press, 2012. Print

Dolphin Safe Tuna

Dolphin Safe Tuna Environmental and animal welfare groups promote dolphin-safe tuna, but the dolphin-safe label is in danger of being weakened in the U.S. and some animal protection groups do not support dolphin-safe tuna. Do Some Cans of Tuna Contain Dolphin Meat? No, cans of tuna do not contain dolphin meat. While dolphins are sometimes killed in tuna fishing (see below), the dolphins do not end up in the cans with the tuna. How are Dolphins Harmed in Tuna Fishing? Two types of tuna fishing are notorious for killing dolphins: Purse seine nets and driftnets. Purse seine nets: Dolphins and yellowfin tuna often swim together in large schools, and because dolphins are more visible and closer to the surface than tuna, the fishing boats will look for dolphins to find the tuna. The boats will then set a purse seine net in a circle around both species and capture dolphins along with the tuna. Purse seine nets are giant nets, typically 1,500 - 2,500 meters long and 150-250 meters deep, with a drawstring at the bottom and floats at the top. Some nets are equipped with fish aggregating devices that attract fish and help prevent the fish from escaping before the net can be closed. In addition to dolphins, the animals who are caught unintentionally - the incidental catch, can include sea turtles, sharks, and other fish. The crew is ususally able to release sea turtles back to the ocean unharmed, but the fish usually die. The problem with dolphins being killed in purse seine nets occurs mainly in the eastern tropical Pacific Ocean. The National Oceanic and Atmospheric Administration estimates that between 1959 and 1976, over 6 million dolphins were killed in purse seine nets in the eastern tropical Pacific Ocean. Driftnets: EarthTrust, an environmental NGO, calls driftnets the most destructive fishing technology ever devised by humankind. Driftnets are giant nylon nets that drift behind a boat. The nets have floats on top and may or may not have weights on the bottom, to keep the net hanging vertically in the water. Driftnets come in a variety of mesh sizes, depending on the target species, but they are a wall of death, killing everyone who gets caught in them. The United Nations banned driftnets over 2.5 kilometers long in 1991. Previously, driftnets up to 60 km long were in use and legal. According to EarthTrust, before the ban, driftnets killed over a hundred thousand dolphins and small cetaceans every year, along with millions of seabirds, tens of thousands of seals, thousands of sea turtles and great whales, and untold numbers of non-target fish. Pirate fisheries still use giant, illegal driftnets and will sometimes cut the nets loose to avoid getting caught, leaving these walls of death to continue drifting and killing indiscriminately for centuries to come. Although dolphin deaths from both methods has been greatly reduced, a 2005 study titled, Non-recovery of two spotted and spinner dolphin populations in the eastern tropical Pacific Ocean found that dolphin populations have been slow to recover. Can Tuna be Caught Without Harming Dolphins? Yes, a purse seine net can be made to release dolphins. After encircling both the tuna and dolphins, the boat can conduct a backdown operation in which a portion of the net is lowered enough for dolphins to escape. While this technique does save dolphins, it does not address other incidental catch issues, such as sharks and sea turtles. Another way to catch fish without harming dolphins is long line fishing. Long line fishing uses a fishing line that is typically 250-700 meters long, with several branches and hundreds or thousands of baited hooks. While longline fishing does not kill dolphins, the incidental catch includes sharks, sea turtles and seabirds like albatross. The Dolphin Protection Consumer Information Act In 1990, the U.S. Congress passed the Dolphin Protection Consumer Information Act, 16 U.S.C. 1385, which charges the National Oceanic and Atmospheric Administration (NOAA) with regulating dolphin-safe tuna claims. The dolphin-safe claim means that the tuna were not caught with drift nets, and that â€Å"no tuna were caught on the trip in which such tuna were harvested using a purse seine net intentionally deployed on or to encircle dolphins, and that no dolphins were killed or seriously injured in the sets in which the tuna were caught.† Not all tuna sold in the U.S. is dolphin-safe. To summarize: If the tuna were caught without driftnets and without chasing, encircling or killing dolphins, it can be sold in the US and is dolphin-safe.If the tuna were caught by chasing and encircling dolphins, but no dolphins were killed or seriously injured (and other requirements are met), the tuna can be sold in the U.S. but cannot be called dolphin-safe.If the tuna was caught by chasing and encircling dolphins, and dolphins were killed, it cannot be sold in the U.S. Of course, the above is a simplification of the law, which also requires tuna canners to file monthly reports and requires large tuna purse seine vessels must carry an observer. NOAA also conducts spot-checks to verify dolphin-safe claims. For more details on the NOAAs tuna tracking and verification program, click here. You can also read the full text of the Dolphin Protection Consumer Information Act here International Law International law also applies to the tuna/dolphin issue. In 1999, the United States signed the Agreement on the International Dolphin Conservation Program (AIDCP). The other signatories include Belize, Colombia, Costa Rica, Ecuador, El Salvador, European Union, Guatemala, Honduras, Mexico, Nicaragua, Panama, Peru, Vanuatu, and Venezuela. The AIDCP seeks to eliminate dolphin mortality in tuna fishing. Congress then amended the Marine Mammal Protection Act (MMPA) to effct the AIDCP in the United States. The AIDCP definition of dolphin-safe allows dolphins to be chased and encircled with nets, as long as dolphins are not killed or seriously injured. This definition differs from the U.S. definition, which does not permit the chasing or encircling of dolphins under the dolphin-safe label. According to the AIDCP, 93% of the sets made by chasing dolphins resulted in no deaths or serious injuries to dolphins. Challeges to the Dolphin-Safe Label Despite the dolphin-safe label being voluntary, and the fact that a fishery need not attain the dolphin-safe label in order to export tuna to the U.S., Mexico has twice challenged the U.S. dolphin-safe label as an unfair restriction on trade. In May of 2012, the World Trade Organization found that the current U.S. dolphin-safe label is inconsistent with the United States obligations under the Agreement on Technical Barriers to Trade. In September, 2012, the U.S. and Mexico agreed that the U.S. would bring its dolphin-safe label in line with the WTOs recommendations and rulings by July of 2013.   To some, this is yet another example of how environmental and animal protection are sacrificed in the name of free trade. Todd Tucker, research director for Public Citizen’s Global Trade Watch, states, â€Å"This latest ruling makes truth-in-labeling the latest casualty of so-called ‘trade’ pacts, which are more about pushing deregulation than actual trade . . . Members of Congress and the public will be very concerned that even voluntary standards can be deemed trade barriers.† Whats Wrong with Dolphin-Safe Tuna? The UK-based Ethical Consumer site calls the dolphin-safe label somewhat of a red herring for several reasons. First, the vast majority of canned tuna is skipjack tuna, not yellowfin tuna. Skipjack tuna do not swim with dolphins, so they are never caught using dolphins. Also, the site points out that, It has been estimated that saving one dolphin, by using (fish aggregating devices), costs 16,000 smaller or juvenile tuna, 380 mahimahi, 190 wahoo, 20 sharks and rays, 1200 triggerfish and other small fish, one marlin and ‘other’ animals. The very strong implication that dolphin-safe tuna is sustainable or more humane makes the label problematic. Some animal protection groups object to dolphin-safe tuna because of the impact on tuna. Tuna and other fish populations are threatened by overfishing and from an animal rights perspective, eating tuna hurts tuna. According to Sea Shepherd, bluefin tuna populations have fallen 85% since industrial fishing began, and current quotas are too high to be sustainable. Environmentalists and animal advocates were disappointed in 2010 when the parties to CITES refused to protect tuna. In September of 2012, conservation experts called for better protections for tuna. According to the International Union for Conservation of Nature, five of the worlds eight tuna species are threatened or nearly threatened. Amanda Nickson, Director of Global Tuna Conservation at the Pew Environment Group stated, There is sufficient science available to set precautionary limits . . . If we wait five, 10 years for the science to be perfect, in the case of some species we may not have anything left to manage. Aside from concerns about extinction and overfishing, fish are sentient beings. From an animal rights perspective, fish have a right to be free of human use and exploitation. Even if there were no danger of overfishing, each individual fish has certain inherent rights, just as dolphins, seabirds and sea turtles do. Buying dolphin-safe tuna recognizes the dolphins rights, but fails to recognize the tunas rights, which is why many animal protection groups do not support dolphin-safe tuna.