Entamoba
Transmission
Ingestion of cysts that are transmitted primarily by the fecal-oral route in contaminated food or water.
Pathogenesis
The ingested cysts differentiate into trophozoites in the ileum but tend to colonize the cecum and colon. Trophozoites invade the colonic epithelium and secrete enzymes that cause localized necrosis. Little inflammation occurs at the site. As the lesion reaches the muscularis layer, a typical flasked-shaped ulcer forms that can undermine and destroy large areas of the intestinal epithelium. Progression into the submucosa leads to invasion of the portal circulation by the trophozoites.
Clinical Syndrome
Dysentery
Lower abdominal discomfort
Flatulence
Tenesmus
Diarrhea
Weight loss
Fatigue
Amebic abscess of liver
Asymptomatic infections
Laboratory Diagnosis
Detecting trophozoites in diarrheal stools or cysts formed in stools.
Epidemiology
Infection occurs worldwide but occurs most frequently in tropical countires, especially in areas with poor sanitation. It is widely prevalent in male homosexuals.
Treatment
Metronidazole or tinidazole
Prevention and Control
Avoiding fecal contamination of food and water and observing good personal hygiene. Purification of water and avoid using human waste to fertilize crops.
Giardia
Transmission
Ingestion of cysts that are transmitted primarily by the fecal-oral route in contaminated food or water.
Pathogenesis
Encystation takes place in the duodenum, where the trophozoites attaches to the gut wall but does not invade. The trophozoites causes inflammation of the duodenal mucosa, leading to malabsorption of protein and fat.
Clinical Syndrome
Watery, foul-smelling diarrhea
Nausea
Anorexia
Flatulence
Abdominal cramps (week to months)
Laboratory Diagnosis
Detecting trophozoites or cysts in diarrheal stools or cysts formed in stools. ELISA test detects a Giardia cyst wall antigen.
Epidemiology
It occurs worldwide. Half of those infected excrete cysts in the stool, which then contaminates water sources. Giardia infection is common in homosexual males, children in day-care centres and patients in mental hospitals.
Treatment
Metronidazole or quinacrine hydrochloride.
Prevention and Control
Drinking boiled, filtered or iodine-treated water in endemic areas and while hiking. No prophylactic drug or vaccine is available.
Cryptosporidium
Transmission
Acquired by fecal-oral transmission of oocysts from either human or animal sources.
Pathogenesis
The oocysts excyst in the small intestine, where the trophozoites attach to the gut wall. Invasion does not occur. The jejunum is the site most heavily infested. The pathogenesis of diarrhea is unknown.
Clinical Syndrome
Watery, nonbloody diarrhea causing large fluid loss and malnutrition
Laboratory Diagnosis
Finding oocysts in fecal smears when using a modified Kiyoun acid-fast stain.
Epidemiology
Cryptosporidia cause diarrhea worldwide. Large outbreaks of diarrhea caused by cryptosporidia in several cities in the United States are attributed to inadequate purification of drinking water.
Treatment
Paromomycin, Nitazoxanide for children aged 1 to 11 years old.
Prevention and Control
Purification of the water supply, including filtration to remove the cysts, which are resistant to the chlorine used for disinfection, can prevent cryptosporidiosis.
Plasmodium
Transmission
Anopheles mosquito
Pathogenesis
Red blood cells are destroyed by the release of merozoites and by the action of the spleen to first sequester the infected red cells and then to lyse them.
Clinical Syndrome
Sudden fever
Chills
Headache
Myalgias
Arthralgias
Nausea
Vomiting
Abdominal pain
Splenomegaly
Anemia
Hepatomegaly in 1/3 of infections
Laboratory Diagnosis
Microscopic examination of thick and thin Giemsa-stained smears. PCR test for Plasmodium nucleic acids. ELISA test for a protein specific P. Falciparium.
Epidemiology
More than 200 million people worldwide have malaria, and more than 1 million die of it each year, making it the most common lethal infectious diseas. IT occurs primarily in tropical subtropical areas, especially in Asia, Africa and Central and South America. Malaria in the United States is seen in Americans who travel to areas of endemic infection without adequate chemoprophylaxis and in immigrants from areas of endemic infection. It is not endemic in the United States. Certain regions in SEA, South America, and east Africa are particularly affect by chloroquine-resistant strains of P. falciparium. People who have lived or traveled in areas where malaria occurs should seek medical attention for febrile illnesses up to 3 years after leaving the malarious area.
Treatment
Chloroquine, Malarone and Mefloquine.
Prevention and Control
Chemoprophylaxis consisting of mefloquine or doxycyline for travelers going to areas where chloroquine-resistant P. falciparium is endemic. Choloroquine used for travelers to areas where other plasmodia are found.
Images
Transmission
Ingestion of cysts that are transmitted primarily by the fecal-oral route in contaminated food or water.
Pathogenesis
The ingested cysts differentiate into trophozoites in the ileum but tend to colonize the cecum and colon. Trophozoites invade the colonic epithelium and secrete enzymes that cause localized necrosis. Little inflammation occurs at the site. As the lesion reaches the muscularis layer, a typical flasked-shaped ulcer forms that can undermine and destroy large areas of the intestinal epithelium. Progression into the submucosa leads to invasion of the portal circulation by the trophozoites.
Clinical Syndrome
Dysentery
Lower abdominal discomfort
Flatulence
Tenesmus
Diarrhea
Weight loss
Fatigue
Amebic abscess of liver
Asymptomatic infections
Laboratory Diagnosis
Detecting trophozoites in diarrheal stools or cysts formed in stools.
Epidemiology
Infection occurs worldwide but occurs most frequently in tropical countires, especially in areas with poor sanitation. It is widely prevalent in male homosexuals.
Treatment
Metronidazole or tinidazole
Prevention and Control
Avoiding fecal contamination of food and water and observing good personal hygiene. Purification of water and avoid using human waste to fertilize crops.
Giardia
Transmission
Ingestion of cysts that are transmitted primarily by the fecal-oral route in contaminated food or water.
Pathogenesis
Encystation takes place in the duodenum, where the trophozoites attaches to the gut wall but does not invade. The trophozoites causes inflammation of the duodenal mucosa, leading to malabsorption of protein and fat.
Clinical Syndrome
Watery, foul-smelling diarrhea
Nausea
Anorexia
Flatulence
Abdominal cramps (week to months)
Laboratory Diagnosis
Detecting trophozoites or cysts in diarrheal stools or cysts formed in stools. ELISA test detects a Giardia cyst wall antigen.
Epidemiology
It occurs worldwide. Half of those infected excrete cysts in the stool, which then contaminates water sources. Giardia infection is common in homosexual males, children in day-care centres and patients in mental hospitals.
Treatment
Metronidazole or quinacrine hydrochloride.
Prevention and Control
Drinking boiled, filtered or iodine-treated water in endemic areas and while hiking. No prophylactic drug or vaccine is available.
Cryptosporidium
Transmission
Acquired by fecal-oral transmission of oocysts from either human or animal sources.
Pathogenesis
The oocysts excyst in the small intestine, where the trophozoites attach to the gut wall. Invasion does not occur. The jejunum is the site most heavily infested. The pathogenesis of diarrhea is unknown.
Clinical Syndrome
Watery, nonbloody diarrhea causing large fluid loss and malnutrition
Laboratory Diagnosis
Finding oocysts in fecal smears when using a modified Kiyoun acid-fast stain.
Epidemiology
Cryptosporidia cause diarrhea worldwide. Large outbreaks of diarrhea caused by cryptosporidia in several cities in the United States are attributed to inadequate purification of drinking water.
Treatment
Paromomycin, Nitazoxanide for children aged 1 to 11 years old.
Prevention and Control
Purification of the water supply, including filtration to remove the cysts, which are resistant to the chlorine used for disinfection, can prevent cryptosporidiosis.
Plasmodium
Transmission
Anopheles mosquito
Pathogenesis
Red blood cells are destroyed by the release of merozoites and by the action of the spleen to first sequester the infected red cells and then to lyse them.
Clinical Syndrome
Sudden fever
Chills
Headache
Myalgias
Arthralgias
Nausea
Vomiting
Abdominal pain
Splenomegaly
Anemia
Hepatomegaly in 1/3 of infections
Laboratory Diagnosis
Microscopic examination of thick and thin Giemsa-stained smears. PCR test for Plasmodium nucleic acids. ELISA test for a protein specific P. Falciparium.
Epidemiology
More than 200 million people worldwide have malaria, and more than 1 million die of it each year, making it the most common lethal infectious diseas. IT occurs primarily in tropical subtropical areas, especially in Asia, Africa and Central and South America. Malaria in the United States is seen in Americans who travel to areas of endemic infection without adequate chemoprophylaxis and in immigrants from areas of endemic infection. It is not endemic in the United States. Certain regions in SEA, South America, and east Africa are particularly affect by chloroquine-resistant strains of P. falciparium. People who have lived or traveled in areas where malaria occurs should seek medical attention for febrile illnesses up to 3 years after leaving the malarious area.
Treatment
Chloroquine, Malarone and Mefloquine.
Prevention and Control
Chemoprophylaxis consisting of mefloquine or doxycyline for travelers going to areas where chloroquine-resistant P. falciparium is endemic. Choloroquine used for travelers to areas where other plasmodia are found.
Images
http://www.google.com/ > Images > entamoeba
http://www.google.com/ > Images > Giardia
http://www.google.com/ > Images > Cryptosporidium
http://www.google.com/ > Images > Plasmodium
Desmond Heng
0503179D
TG02
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