Food infection-Amoebiasis & Hepatitis

 Amoebic dysentery 

•        Amoebic dysentery can be very widespread wherever there is poor hygiene

•        Causative organism: Entamoeba histolytica

•        a protozoan that causes intestinal amoebiasis as well as extraintestinal manifestations.

•        Although 90 percent of E. histolytica infections are asymptomatic, nearly 50 million people become symptomatic, with about 100,000 deaths yearly.

•        usually transmitted by the faecal–oral route.

•        usually through contaminated food or water sources.

•        The organism is an aerotolerant anaerobe which survives in the environment in an encysted form.

•        affects males and females of all ages equally.

•        Factors that are associated with increased risk for complicated infection and mortality are associated with the following: pregnancy, corticosteroid treatment, malignancy, malnutrition, and alcoholism. 

•        There are two forms E. histolytica can take: the cyst form, which can survive in the environment for a prolonged period, and the trophozoite stage, which is the active and invasive form.

•        After the ingestion of the cyst form, trophozoites can be formed, which can invade and penetrate intestinal mucosa destroying epithelial cells and inflammatory cells.

•        The pathological range includes mucosal inflammation, thickening, ulcers, and necrosis, leading to perforation.

•        Indeed, a person with amoebic dysentery may pass up to fifty million cysts per day.

•        most infections remain symptomless

•         illness may start with the passing of mucous and bloody stools, due to ulceration of the colon, a few weeks after infection and progress to severe diarrhoea, abdominal pain, fever and vomiting.

•        Entamoeba histolytica infection is endemic in many poor communities in all parts of the world

 

Hepatitis A

•        Hepatitis A is an inflammation of the liver

•         caused by the hepatitis A virus (HAV). 

•         non enveloped RNA virus

•         spread through food or water that is contaminated with the faeces of an infected person.

•        Outbreaks are usually due to contamination by an infected food handler.  

 

•        The incubation period varies between two and six weeks.

•        During this period the virus multiplies in the cells of the gut epithelium before it is carried by the blood to the liver.

•        In the later part of the incubation period the virus is shed in the faeces.

•        Early symptoms are anorexia, fever, malaise, nausea and vomiting, followed after a few days by symptoms of liver damage such as the passage of dark urine and jaundice.

•        Transmission by oral fecal route

•        Infection is by ingestion

•        It occurs sporadically or as outbreaks

•        Caused by contaminated food and water or milk

•        Shellfish is also responsible

•        Fruits such as strawberries and raspberries, salad vegetables such as lettuce are common food vehicles

•        Domestic or institutional spread is common children.

•        Overcrowding and poor sanitation favor its spread.

 

Hepatitis E

•        Hepatitis E is a liver infection caused by the hepatitis E virus

•        Non enveloped RNA virus

•        The source of infection is fecal contamination of drinking water and the environment.

•        Incubation period –: 2-9weeks

•        Mainly occur to middle aged adults (15-40 years)

•        Infection is self-limiting and resolves within 2–6 weeks.

•        Occasionally a serious disease, known as fulminant hepatitis (acute liver failure) develops, can cause death.

•        Poor sanitation, ingestion of undercooked meat or meat products derived from infected animals (e.g. pork liver) and rarely, transfusion of infected blood products; vertical transmission from a pregnant woman to her baby.

•        Initial phase of mild fever, reduced appetite (anorexia), nausea and vomiting, lasting for a few days; some may also have abdominal pain, itching (without skin lesions), skin rash, or joint pain.

•        Jaundice, with dark urine and pale stools-    a slightly enlarged, tender liver (hepatomegaly).

•        High fatality in pregnant women-   Pregnant women with hepatitis E, particularly those in the second or third trimester, are at increased risk of acute liver failure, fetal loss and mortality.

 Control

•        Safe public water supplies and proper disposal of human faeces.

•        Maintain hygienic practices;

•        Avoiding consumption of water and ice of unknown purity

•        A recombinant subunit vaccine registered in China- not yet been approved in other countries.