Dr. Malik Muhammad Abdul Razzaq Assistant Professor Department of Community Medicine

Dr. Mallik Muhammad Abdul Razzaq

Dr. Malik Muhammad Abdul Razzaq Assistant Professor • Department of Community Medicine • Sheikh Zayed Medical College • Rahim Yar Khan Dr. Mallik Muhammad Abdul Razzaq

Human Intestinal Parasites Dr. Mallik Muhammad Abdul Razzaq

Introduction • Parasite is an organism that lives on or in other organisms from which it obtains nutrients to live and causes harm in the process. • Its name comes from the Greek word para that means beside, and sitos, which means food. • Intestinal parasitic infections (IPIs) are globally endemic and have been described as constituting the greatest single worldwide cause of illness and disease. Dr. Mallik Muhammad Abdul Razzaq

Sources of infection • • Human and animal feces • • walking barefoot • • handling raw meat and fish • • eating raw or undercooked pork, beef or fish • • eating contaminated raw fruits and vegetables • • eating meals prepared by infected food handlers • • drinking contaminated water • • having contact with infected persons (including sexual contact, kissing, and shaking hands) • • inhaling contaminated dust (parasitic eggs or cysts) Dr. Mallik Muhammad Abdul Razzaq

Health Problem • Intestinal parasites are highly prevalent. Poverty has implicated as an important risk factor for infection. Effective poverty reduction programmes and promotion of deworming could reduce intestinal parasite carriage. • There is a need for mass scale campaigns to create awareness about health and hygiene. Ascaris lumbricoides, Trichuris trichiura and hookworms, collectively referred to as soil-transmitted helminths (STHs), are the most common intestinal parasites. Dr. Mallik Muhammad Abdul Razzaq

ASCARIASIS Dr. Mallik Muhammad Abdul Razzaq

Introduction • Ascaris lumbricoides is the largest and the most common helminth parasitizing the human intestine and currently infects about 1 billion people worldwide • An infection of the intestinal tract caused by the adult, Ascaris lumbricoides and clinically manifested by vague symptoms of nausea, abdominal pain and cough. Live worms are passed in the stool or vomited. Dr. Mallik Muhammad Abdul Razzaq

Epidemiological features • AGENT: Ascaris lumbricoides lives in the lumen of small intestine, where it moves freely. Sexes are separate. The female measures 20-35 cm in length, and the male 12-30 cm. Ascaris is a "soil-transmitted" helminthes. The eggs remain viable in the soil for months or years under favorable conditions. Dr. Mallik Muhammad Abdul Razzaq

RESERVOIR OF INFECTION: • Man is the only reservoir. • INFECTIVE MATERIAL: Faeces containing the fertilized eggs, are the sole • HOST: Infection rates are high in children; they are the most important disseminators of infection. • They contribute to malnutrition especially in children who may show growth retardation Dr. Mallik Muhammad Abdul Razzaq

Mode of transmission • It is by the faecal-oral route i.e., by ingestion of infective eggs with food or drink. Foods that are eaten raw such as salads and vegetables readily" convey the infection, and so is polluted water. Other means of spread are by fingers contaminated with soil. • Incubation period • About 2 months. Dr. Mallik Muhammad Abdul Razzaq

PREVENTION AND CONTROL • Primary prevention • Methods based on primary prevention are the most effective in interrupting transmission. These are: sanitary disposal of human excreta to prevent or reduce Faecal contamination of the soil, provision of safe drinking water, food hygiene habits, and health education of the community in the use of sanitary latrirines; personal hygiene and changing behavioral patterns. Dr. Mallik Muhammad Abdul Razzaq

Secondary prevention • Effective drugs are available for the treatment of the human reservoir. These are piperazine, mebendazole, levamisole and pyrantel; the last two drugs are effective in a single dose. • MASS TREATMENT: Periodic de-worming at intervals of 2 to 3 months may be undertaken. This may be needed where parasites and protein-energy malnutrition are highly prevalent. Dr. Mallik Muhammad Abdul Razzaq

HOOKWORM INFECTION • Hookworm infection is defined as "any infection caused by Ancy/ostoma duodenale or Necator americanus". They may occur as single or mixed infections in the same person. Dr. Mallik Muhammad Abdul Razzaq

Agent factors • AGENT : Adult worms live in the small intestine, mainly jejunum where they attach themselves to the villi. Males measure 5 to 11 mm, and females 9 to 13 mm in length with dorsally curved anterior end. Eggs are passed in the faeces in thousands; • RESERVOIR : Man is the only important reservoir of human hookworm infection, Dr. Mallik Muhammad Abdul Razzaq

INFECTIVE MATERIAL • Faeces containing the ova of hookworms. However, the immediate source of infection is the soil contaminated with infective larvae, PERIOD OF INFECTIVITY : As long as the person harbours the parasite. Dr. Mallik Muhammad Abdul Razzaq

Host factors • AGE AND SEX: All ages and both sexes are susceptible to infection. In endemic areas, the highest incidence is found in the age group, 15 to 25 years, • NUTRITION : Studies indicate that malnutrition is a predisposing factor; the chronic disabling disease does not occur in the otherwise healthy individual who is well-nourished and whose iron intake is adequate, Dr. Mallik Muhammad Abdul Razzaq

Environmental factors • Hookworm larvae live in the upper half-inch (1.2 cm.) of the soil. Favorable environmental conditions are, therefore, crucial for the survival of the hookworm larvae in the soil Dr. Mallik Muhammad Abdul Razzaq

Mode of transmission • Hookworms (infective larvae) enter the body, usually feet, by penetrating the skin. Ancylostoma rnay also be acquired by the oral route by direct ingestion of infective larvae via contaminated fruits and vegetables. Transmission is perennial in many tropics. In cooler and drier climates, transmission may take place in the warmer and wet seasons. Dr. Mallik Muhammad Abdul Razzaq

Incubation period (prepatent period) • Following infection, the prepatent period for N. americanus is 7 weeks while that for A. duodenale is unpredictable, ranging from 5 weeks to 9 months. This is because the invading larva of A. duodenale is capable of remaining arrested or dormant in the tissues of the host for as long as 9 months and then again resume development and migration Dr. Mallik Muhammad Abdul Razzaq

Effects of the disease • Blood loss and depletion of body's iron stores leading to iron-deficiency anaemia. This has implications for child health in terms of retarded physical growth and development; for the health of mothers in terms of increased morbidity, low birth weight babies, abortion, stillbirths and impaired lactation. Dr. Mallik Muhammad Abdul Razzaq

PREVENTION AND CONTROL • The prevention and control of hookworm infection involves four approaches • - sanitary disposal of faeces • - chemotherapy • - correction of the anaemia, and • - health education Dr. Mallik Muhammad Abdul Razzaq

DRACUNCULIASIS • Dracunculiasis or guineaworm disease is a vector borne parasitic disease, mainly of the subcutaneous tissues (usually leg and foot) caused by the nematode parasite, Dracunculus medinensis. Although not lethal, this parasitic disease can disable its victim temporarily. Dr. Mallik Muhammad Abdul Razzaq

Mode of transmission • The disease is transmitted entirely through the consumption of water containing cyclops harbouring the infective stages of the parasite. Guinea worm disease is a totally water-based disease and does not have an alternate pathway of transmission Dr. Mallik Muhammad Abdul Razzaq

Eradication • Guineaworm disease is amenable to eradication. The eradication strategy comprises the following elements : • i) Provision of safe drinking water (e.g., piped water, installation of hand pumps) Control of cyclops • Health education of the public in matters relating to boiling or sieving drinking water through a double-thickness cotton cloth for personal protection, and prevention of water contamination by infected persons. Dr. Mallik Muhammad Abdul Razzaq

THE DENGUE SYNDROME • Dengue viruses are arboviruses capable of infecting humans, and causing disease. These infections may be asymptomatic or may lead to • (a) "classical" dengue fever, • (b) dengue haemorrhagic fever without shock, • (c) dengue haemorrhagic fever with shock.. Dr. Mallik Muhammad Abdul Razzaq

Classical Dengue Fever • . It is an acute viral infection, caused by at least 4 serotypes (1,2, 3 and 4) of dengue virus. Dengue fever can occur epidemically or endemically. Epidemics may be explosive and often start during the rainy season when the breeding of the vector mosquitoes (e.g., Aedes aegypti) is generally abundant. Dr. Mallik Muhammad Abdul Razzaq

Environmental Factors • Temperature also plays an important role in the transmission of dengue virus by mosquitoes. Mosquitoes kept at 26°C fail to transmit DEN-2 virus. Hence, the low incidence of DHF in certain seasons could be explained by this observation. • Vector • Aedes aegypti is the main vector. Dengue outbreaks have also been attributed to Aedes albopictus, Aedes polynesiensis, and several species of the Aedes scutellaris complex Dr. Mallik Muhammad Abdul Razzaq

Transmission Cycle . The transmission cycle is "Man-mosquito-Man". The reservoir of infection is both man and mosquito. • The Aedes mosquito becomes infective by feeding on a patient from the day before onset to the 5th day (viraemia stage) of illness. • After an extrinsic incubation period of 8 to 10 days, the mosquito becomes infective, and is able to transmit the infection. Once the mosquito becomes infective, it remains so for life. Transovarian transmission of dengue virus has been demonstrated in the laboratory. Dr. Mallik Muhammad Abdul Razzaq

Epidemiological Factors • Host factors • All ages and both sexes are susceptible to dengue fever. Children usually have a milder disease than adults. • Incubation Period • The illness is characterised by an incubation period of 3 to 10 days (commonly 5-6 days). Dr. Mallik Muhammad Abdul Razzaq

Clinical Features • Specific Symptoms • The onset is sudden with chills and high fever, intense headache, muscle and joint pains, which prevent all movement. Within 24 hours retro-orbital pain, particularly on eye movements or eye pressure and photophobia develops. .Fever lasts for about 5 days, rarely more than 7 days after which recovery is usually complete although convalescence may be protracted. The case fatality is exceedingly low Dr. Mallik Muhammad Abdul Razzaq

Common Symptoms • These include extreme weakness, anorexia, constipation, altered taste sensation, colicky pain and abdominal tenderness, dragging pain in inguinal region, sore throat and general depression. Fever is usually between 39°C and 40°C. Fever is typically but not inevitably followed by a remission of a few hours to 2 days (biphasic curve Dr. Mallik Muhammad Abdul Razzaq

Characteristic Skin Rash • The rash may be diffuse flushing, mottling or fleeting pin-point eruptions on the face, neck and chest during the first half of the febrile period and a conspicuous rash, that may be maculopapular or scarlatiniform on 3rd or 4th day. It starts on the chest and trunk and may spread to the extremities and rarely to the face. It may be accompanied by itching and hyperaesthesia. The rash lasts for 2 hours to several days and may be followed by desquamation . Dr. Mallik Muhammad Abdul Razzaq

Dengue Haemorrhagic Fever • Dengue haemorrhagic fever (DHF) is a severe form of dengue fever, caused by infection with more than one dengue virus. The severe illness is thought to be due to double infection with dengue viruses the first infection probably sensitizes the patient, while the second appears to produce an immunological catastrophe . DHF is transmitted by A. aegypti. • Incubation Period • The incubation period is of four to six days. Dr. Mallik Muhammad Abdul Razzaq

Clinical Features • During the first few days the illness usually resembles classical DF, but maculopapular rash usually rubelliform type, is less common. It may appear early or late in the course of the illness. Occasionally, the temperature may be 40°C to 41 °C and febrile convulsions may occur particularly in infants. Dr. Mallik Muhammad Abdul Razzaq

Patho-physiologic Changes • There is plasma leakage and abnormal haemostasis, as manifested by a rising haematocrit value and moderate to marked thrombocytopenia. These two clinical laboratory changes are distinctive and constant findings. Dr. Mallik Muhammad Abdul Razzaq

Clinical diagnosis • Fever - acute onset, high, continuous, and lasting 2 to 7 days • Haemorrhagic manifestations, including at least a positive tourniquet test Any of the following may be present. • - petechiae, purpura, ecchymosis • - epistaxis, gum bleeding • - haematemesis and/or melaena Enlargement of liver Dr. Mallik Muhammad Abdul Razzaq

Grading of severity of DHF • Grade I: Fever accompanied by non-specific constitutional symptoms. The only haemorrhagic manifestation is a positive tourniquet test. • Grade // : Patient with spontaneous bleeding usually in the form of skin and/or other haemorrhages in addition to the manifestations in grade I. Dr. Mallik Muhammad Abdul Razzaq

Grade III: Circulatory failure manifested by rapid and weak pulse, narrowing of pulse pressure (20 mm Hg or less) or hypotension with the presence of cold clammy skin and restlessness. • Grade IV: Profound shock with undetectable blood pressure and pulse. Dr. Mallik Muhammad Abdul Razzaq

Laboratory diagnosis (a) Thrombocytopenia (100,000/mm3 or less) (b) Haemoconcentration; haemotocrit increased by 20 per cent or more of base-line value The first two clinical criteria plus thrombocytopenia and haemoconcentration or a rising haematocrit are sufficient to establish a clinical diagnosis of DHF . Dr. Mallik Muhammad Abdul Razzaq

Dr. Malik Muhammad Abdul Razzaq Assistant Professor Department of Community Medicine