Morbidity and Mortality Weekly Analysis of the Disease Cryptosporidiosis - Term Paper Example

 Morbidity and Mortality Weekly Report on the disease Cryptosporidiosis Cryptosporidiosis is a disease of the intestines caused by a parasite known as Cryptosporidium. This is a protozoan parasite which causes illness by infecting the intestinal and respiratory epitheliums of humans, reptiles and mammals (Levine, 1973). This parasite was first identified in the gastric glands of mice back in 1907, but its pathogenecity was not established until the late 1970’s when it was acknowledged as being one of the major causes of enterocolitis and diarrhea in both calves and humans (Tzipori, p. 884-886). Majority of the Cryptosporidium species belong to the Eimeria genre and mostly resemble entero-cocci bacteria in their pathogenecity. Cryptosporidium hominis, Cryptosporidium parvum, Cryptosporidium meleagridis, Cryptosporidium felis and Cryptosporidium canis have been identified as the major types of Cryptosporidium that cause infection in humans. While presence of C. canis, C. felis and C. meleagridis has been confirmed in AIDS patients. They have the capability to infect both immuno-competent and immuno-compromised individuals (Tzipori, p. 884-886). It considered an important source of morbidity and mortality in young children. Every year about 400-500 people in New York alone are infected by the parasite. It has been known to cause short term diarrhea in young children but if severe may even cause long term problems in immuno-compromised persons (Guerrant, p. 707-13). This parasite is usually found in the soil food and water, or surfaces that are known to come in contact with feces. It is how ever not known to spread via contact with blood (CDC). Most Infections tend to spread by the oral-fecal route. That entails the droppings of an infected animal and the transmission of the parasite via the mouth. This parasite can also spread by person to person, by eating contaminated food and by drinking contaminated water. It is in fact because the parasite is transmitted via the oral fecal route that it is often found in people with poor hygiene, diapered children and people with diarrhea. The infection can also spread by eating contaminated, uncooked food and also by touching hands which may be infected with the parasite to the mouth. Exposure to feces via sexual contact may also be one more source of infection (CDC). Never the less it is important to note that a short term infection may have long term consequences (Guerrant, p. 707-13). The degree of infection is usually directly related to the severity and onset of disease. Some adults with incompetent immune systems such as seen widely in HIV positive patients may even be infected with more than one type of genus of Cryptosporidium or in worse cases more than one type of organism. Adult human beings with congenitally suppressed illness are very likely to develop several severe forms of the disease. Also more prone to infection are individuals with a HIV positive serotype. As mentioned earlier due the nature of their fragile immune system they are much more at risk of developing a sever form of the ill caused by the Cryptosporidium. There have been several studies citing the reasons for the increased susceptibility of a cryptosporidium infection in some persons while others are somewhat immune to it. Firstly it is very important to note here that Cryptosporidium works by suppressing the ability of the small intestine to digest and absorb food. The investigation into weather Cryptosporidium causes disease either by the destruction of the mucosal lining of the small intestine or by the release of harmful toxins or by the discharge of parasitic metabolites is still on going. In most cases it has been observed that infected animals tend to develop dramatic changes in the mucosa as well as very strong inflammatory reactions. Other investigations have also shown that certain genus may produce host specific reactions in particular organs. For example it has been noticed that mouse, cat and guinea pig isolates propagate more readily in their respective hosts as compared to others. The disease may cause severe brush border mal-digestion and to larger extent mal-absorption from the altered architecture of mucosa of the intestines. Death usually occurs due to dehydration and acidosis. It achieves this by blocking the mucosal layer of the small intestine several human and calf biopsies often small intestine have often showed sever atrophy of the villi as well as complete or partial destruction of the mucosal epithelium of the intestine. This as a result caused severe mal-absorption in individuals which subsequently lead to severe malnutrition and in worsening cases even death (Anderson, p.982-984). In other studies when the prevalence of the disease of observed, it was noted that through the months of February through May, persons complaining of gastroenteritis were around 7% more likely to be infected with Cryptosporidium than others, for the rest of the year the likelihood as such dropped to around 2%. The most common symptom was diarrhea accompanied with severe nausea, vomiting, abdominal pain and even anorexia. Typically these symptoms would last around 14-15 days. While the incubation period of the parasite after infection is usually about two weeks. The presence of Cryptosporidium oocytes in feces usually confirms the infection in most human patients (Tzipori, p. 884-886). While permanent immunity may never be established it has been reported that exposure to a large dose of the parasite would result in subsequent chronic illness. There are no known treatments for a Cryptosporidium infection. Some patients however respond to certain antibiotics. In other instances oral liquids and intravenous fluids may be given to treat the severe dehydration that occurs as result of infection. Sometimes an anti-diarrheal drug may be given to provide temporary relief to the patient. Immuno-compromised persons should therefore be extra careful and take necessary precautions with the advice from their health care advisor to prevent them selves from being infected. Some of the steps that can reduce the risk of infection could be the following. Firstly hands should always be thoroughly washed when ever coming in contact with fecal matter such as changing diapers or soiling. Secondly, avoid exposure to all kinds of farm animals, or if this cannot be avoided than hands should be washed immediately there after. Even fresh food such as fruits and vegetables should be thoroughly washed before eating. Water is a major source of infection. Hikers, adventurists etc should take extra care when choosing to drink water directly from fresh water sources such streams, rivers and lakes. All can be dangerous sources of infection. Even swimmers should avoid drinking pool water or water from any other water body that can be a source of infection. Water should therefore always be distilled and purified when made available for drinking purposes (New York state department of health). The above graph shows the incidence of the parasitic disease over the past year. With incidence of the disease peaking in the 25th to 29th week (month of June till July). Cryptosporidiosis is a serious infection which mainly infects mainly children in topical countries. International travelers are also at high risk for the disease. Future studies into the mechanism of infection and treatments could open up the possibilities of preventing this disease. For now the best possibility is to work on preventing the spread of infection. The best way is to make sure that drinking water is made safe. Communities where the latest sanitation techniques are unavailable could try and boil water to improve the chances of prevention. In other instances high levels of chlorine are known to prevent infection but these studies differ on a case by case basis. (CDC) Fact: In 1993 an out break in Wisconsin USA killed around 100 people while infecting another 4400. Cryptosporidium will usually infect more people from developing countries than developed ones. High incidences of the parasite have been reported between the months of Feb till may. This may suggest that the parasite may be much more pathogenically active during milder temperatures. The incidence is affected greatly during winter months. A drug called Nitazoxanide has been successful in treating HIV positive patients infected with the parasite. In birds the parasite has been found to infect the respiratory tract instead of the intestine while the oocytes of the parasite are not found to be excreted in feces of birds. People with good immune systems may be positive for infection but may never develop illness from the parasite. (CDC) References Guerrant DI, Moore SR, Lima AA, Patrick PD, Schorling JB, Guerrant RL: Association of early childhood diarrhoea and cryptosporidiosis with impaired physical fitness and cognitive function 4-7 years later in a poor urban community in northeast. Brazil. Am J Trop Med Hyg 1999, 61:707-13. Levine, N. D. 1973. Protozoan parasites of domestic animals and man, p. 229-230, 2nd ed. Burgess Publications, Minneapolis. Tzipori, S., K. W. Angus, I. Campbell, and E. W. Gray. 1980. Cryptosporidium: evidence for a single species genus. Infect. Immun. 30:884-886. Anderson, B. C. 1981. Patterns of shedding of cryptosporidial oocysts in Idaho calves. J. Am. Vet. Med. Assoc. 178:982-984 CDC reference: http://www.cdc.gov/crypto/gen_info/infect.html Read More