1. Concept & Etiology: A parasite is an organism that lives on or in
a host organism and gets its food from or at the expense of its
host. There are three main classes of parasites that can cause
disease in humans: protozoa, helminths, and ectoparasites. a A
wide range of parasitic infections can involve the skin and
subcutaneous tissues. Parasitic diseases are illnesses caused by
infestation (infection) with parasites such as protozoa (one-
celled animals), worms, or insects. These diseases are
widespread in Africa, southern Asia, and Central and South
America, especially among children. They include malaria and
schistosomiasis, the world's most common serious infectious
diseases. Depending on the species of parasite, this
involvement may be transient, the parasite passing through the
skin on its migration to the bloodstream and so to a specific
target organ, or the infection may be localized to the skin. In the
latter infections, the skin may be the primary site of infection or
there may be a secondary invasion of the skin. All parasitic
groups (protozoa, trematodes, cestodes, nematodes, and
arthropods) have species that can involve the skin or
subcutaneous tissues.
a a a 2. Classification:
The protozoa that are infectious to humans can be classified into four
groups based on their mode of movement:
• Sarcodina – the ameba, e.g., Entamoeba
• Mastigophora – the flagellates, e.g., Giardia, Leishmania
• Ciliophora – the ciliates, e.g., Balantidium
• Sporozoa – organisms whose adult stage is not motile e.g.,
Plasmodium, Cryptosporidium
Parasitic infections cause a tremendous burden of disease in both the
tropics and subtropics as well as in more temperate climates.
There are three main groups of helminths (derived from the Greek
word for worms) that are human parasites:
• Flatworms (platyhelminths) – these include the trematodes
(flukes) and cestodes (tapeworms).
• Thorny-headed worms (acanthocephalins) – the adult forms of
these worms reside in the gastrointestinal tract. The
Acanthocephala are thought to be intermediate between the
cestodes and nematodes.
• Roundworms (nematodes) – the adult forms of these worms can
reside in the gastrointestinal tract, blood, lymphatic system, or
subcutaneous tissues.
Although the term ectoparasites can broadly include blood-sucking
arthropods such as mosquitoes (because they are dependent on a
blood meal from a human host for their survival), this term is generally
used more narrowly to refer to organisms such as ticks, fleas, lice, and
mites that attach or burrow into the skin and remain there for
relatively long periods (Ex: weeks to months).
a a a 3. Clinical Manifestations (Symptoms and Signs): Gas, bloating,
constipation, diarrhea, nausea, vomiting, stomach pain, greasy loose
stool, worms, parasites, mucus, eggs or candida yeast in stool, skin
rashes and skin issues such as eczema, hives, Unexplained weight loss
or weight gain, nutritional deficiencies, dehydration, fever, and many
more different signs and symptoms.
a a a 4. Diagnostic Tests: There are various lab tests that doctors
and health providers typically use to detect and diagnose parasitic
infections in the body. Finding the most accurate parasite test,
however, may be a challenge, since a negative parasite test doesn’t
mean you do not have a parasitic infection. Several tests are usually
conducted. The parasite symptoms you can share with your doctor
are very important as they may indicate a specific parasitic infection.
This can help your doctor to order the right test. Some tests include
Fecal stool test, ova (eggs), parasite test, Endoscopy (mouth),
Colonoscopy (rectum), Blood test: Serology or Smear test, X-ray, MRI,
CAT scans, and a Pinworm test or Scotch tape test can be done.
These tape tests look for pinworms using scotch tape around the
anus to collect pinworm eggs. The tape is sent to the lab and is
checked under a microscope for eggs.
References
Candida Specialists (Ed.). (2019, May 25). Parasite symptoms in
humans: Do you have these common signs? Candida and Yeast
Infection Specialists Healing Center. Retrieved December 2, 2021,
from https://candidaspecialists.com/parasite-symptoms/.
U.S Department of Health and Human Services. (2020, September
18). CDC - parasites - about parasites. Centers for Disease Control and
Prevention. Retrieved December 2, 2021, from
https://www.cdc.gov/parasites/about.html#:~:text=The%20protozo
a%20that%20are%20infectious%20to%20humans%20can,stage%20i
s%20not%20motile%20e.g.%2C%20Plasmodium%2C%20Cryptospor
idium.%20.
