Solution:
Entamoeba histolytica is a protozoan parasite in the large intestine of human which causes amoebiasis ( amoebic dysentery ).
Symptoms of this disease include constipation, abdominal pain, and cramps, stools with excess mucous and blood clots.
Houseflies act as mechanical carriers and serve to transmit the parasite from faeces of an infected person to food and food products, thereby contaminating them.
Drinking water and food contaminated by the faecal matter are the main sources of infection.
Ascaris , the common roundworm , and Wuchereria , the filarial worm , are some of the helminths which are known to be pathogenic to man.
Ascaris, an intestinal parasite causes ascariasis.
Symptoms of this disease include internal bleeding, muscular pain, fever, anaemia, and blockage of the intestinal passage.
The eggs of the parasite are excreted along with the faeces of infected persons which contaminate soil, water, plants, etc.
A healthy person acquires this infection through contaminated water, vegetables, fruits, etc.
Wuchereria ( W. bancrofti and W. malayi ), the filarial worms cause a slowly developing chronic inflammation of the organs in which they live for many years, usually, the lymphatic vessels of the lower limbs, and the disease are called elephantiasis or filariasis .
The genital organs are also often affected, resulting in gross deformities .
The pathogens are transmitted to a healthy person through the bite of the female mosquito vectors.
Many fungi belonging to the genera Microsporum , Trichophyton , and Epidermophyton are responsible for ringworms which is one of the mostcommon infectious diseases in man.
The appearance of dry, scaly lesions on various parts of the body such as skin, nails, and scalp are the main symptoms of the disease.
These lesions are accompanied by intense itching. Heat and moisture help these fungi to grow, which makes them thrive in skin folds such as those in the groin or between the toes.
Ringworms are generally acquired from soil or by using towels, clothes, or even the comb of infected individuals.
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