What are the common parasitic diseases and how can they be prevented?

Parasitic diseases are a diverse group of health conditions that occur when a parasite relies on the human body for food and shelter. These organisms range from microscopic single-celled protozoa like the parasite Giardia and Cyclospora, to intestinal worms that can be seen with the naked eye [1]. The nature of each infection varies depending on the causative organism, making a precise understanding of their transmission and prevention essential for maintaining public health.

Transmission Methods of Parasitic Infections

Parasitic infections are mainly spread through the consumption of water or food contaminated with human feces containing the parasite or infectious stages such as cysts. In many cases, infection is transmitted through eating vegetables or fruits that have not been cleaned well or drinking unsafe water, especially in areas where these parasites are prevalent [1]. Transmission methods are not limited to food; some parasites can be transmitted through insect bites, direct contact, or sexual contact, while some parasites, like Cyclospora, require a period of time outside the body (days to weeks) to become infectious to humans, which reduces the chances of direct transmission from person to person [3].

Common Symptoms and the Necessity of Medical Review

Symptoms are often concentrated in the digestive system, including frequent watery diarrhea, abdominal pain, bloating, gas, nausea, and loss of appetite. In some infections, such as Cyclospora, these symptoms may be accompanied by fatigue, headache, and a mild fever similar to flu-like symptoms [3]. It is essential not to neglect these symptoms; it is advised to consult a doctor immediately if diarrhea or severe symptoms persist for more than three days, or upon the appearance of signs of severe dehydration. This review is especially necessary for children, the elderly, and people with weakened immune systems, as complications may worsen more quickly for them [3].

Effective Diagnosis and Prevention

Accurate medical diagnosis depends on laboratory tests, most notably the stool examination (Ova and Parasite Test) to detect parasites or their eggs under a microscope [1]. Prevention methods vary depending on the parasite and the way it is exposed, and it is not correct to generalize a single procedure for all parasitic diseases [1]. Appropriate measures for many food and waterborne parasites include the following:

• Handwashing: Commit to washing hands thoroughly with warm water and soap for at least 20 seconds before and after preparing food, and after using the toilet [3].
• Washing Vegetables: Rinse all fruits and vegetables under clean running water, discard the outer layers of leafy greens whenever possible, and avoid using chemical detergents as a substitute for mechanical washing [3].
• Proper Cooking: Follow food safety cooking instructions according to the type of food, and do not rely on washing produce alone to ensure the removal of all parasites. The resistance of parasites to heat and disinfection varies by type [3].
• Safe Sources: Avoid drinking unreliable water or water from rivers and ponds, and rely on safe and treated water sources, especially when traveling [1].

For more information on preventive measures, you can read our article on Common Parasitic Diseases: Prevention, Diagnosis, and Treatment (Arabic).

Medical references

• Parasitic Diseases
• Cyclospora