Home Health Microbes Parasites Ectoparasites


Ectoparasites live outside on the human body.
Endoparasites live inside the human body, eg., amoebas, worms, or flukes.

The following are some common Ectoparasites.

Common bedbugs (Cimex lectularius)
Are flattened, oval, reddish brown insects that inhabits houses, furniture, and neglected beds. They feed on man, usually at night, causing itchy bites.

Human fleas (Pulex irritans)
Are small, wingless, bloodsucking insects that act as vectors for the spread of such diseases as plague, tularemia, and brucellosis.

Are any of the annelids from the class Hirudinea, especially Hirudo medicinalis. Some species are bloodsuckers and were once used to draw blood out of those who were ill.

Lice (singular louse)
Are grayish, wingless, and somewhat flattened parasetic insects that belong to the suborder Anoplura. They are usually found in crowded areas with poor sanitation and hygiene. Infestations are called pediculosis. Lice live on the blood of a host, obtained by piercing the skin and sucking the blood through their mouth parts. The area bitten becomes itchy and inflammed, and often infected from scratching. They are often vectors transmitting such diseases as typhus. Those parasitic to humans are:
  1. Human body louse (Pediculus humanus corporis) lives on the body and clothes of man.
  2. Head louse (Pediculus humanus capitis) attaches itself to the hairs of the head, and are noted for causing endemic outbreaks in school children.
  3. Pubic or crab louse (Phthirus pubis) is often sexually transmitted. It resembles a miniature crab, and causes intense itching in the pubic area, but it can also infect the eyebrows, eyelashes, and beards.

Are arthropods belonging to the order Acarina. They differ from ticks in that they are minute and usually either transparent or semitransparent. They are sometimes called chiggers. Mites often burrow into the skin, causing intense itching resulting in inflammed areas of the skin. Mites live under four days outside the body. Some of the common ones that affect man include:
  1. Dust mites (Dermatophagoides farinae and D. Pteronyssinus) are, as the name implies, found in all manner of dust, indoors and out.
  2. Face mites and follicle mites (Demodex brevis and D. Folliculorum) are also, as the name implies, found as a normal part of the face. Obviously, they are microscopic.
  3. Chiggers (Eutrombicula alfreddug├Ęsi, E. splendens, Trombicula autumnalis, etc.) are six-legged red larvae of the mite family Trombiculidae, also known as the harvest mite or the red bug. Chiggers attach to the skin of a host and bite, causing a wheal of intense itching and severe dermatitis. Some species are vectors of the rickettsiae that causes scrub typhus.
  4. Itch mites (Sarcoptes scabiei) cause the condition known as scabies. This mite lays its eggs in tunnels in the skin, where it takes about two weeks for them to hatch. Symptoms include intense itching, especially at night, with a rash, particularly on the hands, and arms, armpits, and genitalia. This infection often goes unnoticed in severely retarded or senile people, who are not able to scratch. Norweigan scabies is a rare, but a more severe, form. It is common for an adult infested with scabies to have only about elevven adult mites on his body, but a person with Norweigan scabies can be infested with two million. The skin becomes covered with thick crusts, but the itching is milder than the other form. Those with deficient immune systems or senility often fall victim to this form, but the same mite is responsible for both, which are acquired through close prolonged contact with an infected person. The standard treatment is with a topical chlorinated hydrocarbon insecticide called “lindane,” a benzene hexachloride. This can be toxic to the blood and nervous system and should not be used on children or pregnant women or those with a history of seizure disorders. Plus, there is evidence that scabies are now becoming resistant to this treatment. Another drug used orally is “ivermectin,” which has been linked to an increased number of deaths in nursing home patients. Less toxic treatments include the antiparasitic drugs permethrin, crotamiton, sulfur, and benzyl benzoate. Systemic antibiotics are often used to treat or prevent secondary infections that sometimes come from scratching. Since scabies is not a life-threatening disease, alternative methods of treatment should be considered first. Historic treatments include buckbean or bogbean (Menyanthes trifoliata), pansy (Viola tricolor), and pine (Pinus palustris). An extract of aniseed (Pimpinella anisum) applied to the skin has also been used. A strong herbal tea for washing the skin is suggested, as well as using several available essential oils. Diluting the suggested oil in a carrier oil and applying to the skin is also an effective method. A knowledgeable person in this area can give more advice. Improvements are seen only after several applications. However, it is much healthier to take the time now, than pay later. By using the oils, mites will suffocate, and the oils will heal the areas they have invaded. The old standby, garlic in the oil form, can also be used. Other suggested oils include the following: tea tree oil (Melaleuca alternifolia), clove oil (Eugenia caryophyllata), Patchouli essential oil (Pogostemon cablin), lavender (Lavandula angustifolia), lemon (Citrus limonum), Rosemary (Rosmarinus officinalis), Orange flower (Citrus aurantium), Cinnamon (Cinnamomum zeylanicum), Mustard (Sinapis spp), and Thyme (Thymus vulgaris).

Tooth amoebas (Entameba gingivalis)
Are microscopic parasites that hide in the tiny crevices where the teeth meet the gums. Brushing does not remove them because they change shape to conform to their hiding places. As a beneficial organism, they eat mouth bacteria and only become harmful when the lack of hygiene forces them to multiply too quickly.

Ticks (see also Rickettsia)
Are blood-sucking arachnid parasites that are seen by the naked eye and act as vectors for certain bacteria known to cause disease in humans. They are the only venonous creature that hunts down humans. Others try to avoid them. There are two kinds of ticks: hard and soft; and each carries different diseases. Soft ticks do not burrow into the skin. Hard ticks do, and must be removed with care, keeping their heads intact. Dog ticks bring slow paralysis and even death to children.

Tick diseases include the following: Lyme disease; Colorado tick fever; Rocky Mountain Spotted fever; Russian spring encephalitis; Russian summer encephalitis; louping ill; Negishi encephalitis; Omsk hemorrhagic fever; Kyasanur forest disease; Langat encephalitis; royal farm virus; Powassan encephalitis; Bhanja virus; Nairobi sheep disease; relapsing fever; tularemia; Siberian tick typhus; Boutonneuse fever; Japanese river fever; Tsutsugamushi disease; Kemorovotick fever.

Lyme Disease is caused by a spirochete (Borrelia) on a tick vector (Ixodes dammini). The disease is multisystemic, causing after recovery complaints of arthritis of the large joints, myalgia, malaise, and neurologic and cardiac manifestations. The Borrelia are parasitic organisms responsible for several diseases (including relapsing fever) transmitted by ticks and the human body louse. No studies have ever been done to investigate treating Lyme disease with herbs, but there have been studies that show prophylactic treatment with antibiotics has not halted the development of the disease at all. Since antibiotics are administered for four to six weeks, there are herbs that can be taken at the same time to lessen the damage done to the body. Probiotics, in the form of tablets or live culture in yogurt, can minimize damage to the intestinal tract. Taking garlic, echinacea, and beta carotene will help support the immune system, and the B vitamins will reduce nerve damage done in later stages of the disease.

Australian paralysis ticks cause the same type of paralysis in humans, but the opposite occurs when it is removed – paralysis becomes worse rather than improving.

Tropical chigoes or jiggers (Tunga penetrans)
Are found in the tropical and subtropical America and Africa. The pregnant female burrows into the skin of the feet, legs, or other parts of the body. This causes intense itching and irritation that sometimes results in ulcerations. If left untreated, amputation is sometimes necessary.