giardia lamblia

2. INTRODUCTION
The first parasitic protozoan was seen in 1681 by Antony Van Leeuwenhoeck; through his
rudimentary microscope, in a sample of his own fecal matter, which corresponded to the
flagellate GIARDIA. This finding was communicated in a letter to the Royal Society of London,
but it was described as a protozoan that had no significance for medicine at the time, and had to
be rediscovered by the Czech professor of pathological anatomy: Vilem Lamb of the University
of Prague, who 178 years later (1859), saw the protozoan in the gelatinous feces of a child. The
researcher made two publications of this finding and illustrated his reports with various drawings
of trophozoites and cysts. He compared them to tadpoles and gave them the name Cercomonas
Intestinalis. Grassi (1879) found the same parasites in mice, and Blanchard (1885) observed
similar parasites in tadpoles and named them Giardia agalis. The genus was named in honor of
the zoologist Alfred Giard who had nothing to do with the parasite. Blanchard, in the same year,
recognized Lamb as the discoverer and named it Lamblia Intestinalis. Stiles (1915) put the two
names together and called them Giardia Lamblia. The controversy persisted until (1952), when
Filice proposed the names Giardia Intestinalis and Giardia Duodenalis. Currently the most
accepted is Giardia Intestinalis.

3. The parasite is a flagellated protozoan and in recent years
several genotypes have been described, with different
pathogenic capacity both in humans and in animals.
The trophozoite of G.Intestinalis has a pear-shaped shape and
in the anterior part it has nuclei that join each other in the
center, with the appearance of spectacles. It measures
approximately 15u in length, by 7u in width. It has a cavity or
sucker that occupies the anterior half of its body, which it uses
to attach itself to the intestinal mucosa. It has in its longitudinal
diameter and in the central part, a double bar or axostyle from
whose anterior end four pairs of flagella emerge: one anterior,
two lateral and one posterior.
GIARDIA LAMBLIA

4. LIFE CYCLE OF GIARDIA
LAMBLIA

5. Repeated infections in childhood
produce protective antibodies. Adults in
non-endemic areas are more
susceptible to infection than those
living in endemic areas. There is a
commercial vaccine for giardiasis in
dogs and cats, but not for humans.
IMMUNITY

6. 1.1. CLINICAL MANIFESTATIONS
 Asymptomatic infection: We have found that in school children from poor
endemic areas in Colombia, 50% of those who have Giardia cysts on stool
examination have no symptoms. Adults in general are more often asymptomatic
than children. In people with these parasites in endemic areas, the presence of
symptoms and the intensity of symptoms are lower than in visitors from non-
endemic areas who suffer from giardiasis.
 Acute giardiasis:
More common in non-immune travelers, who are affected upon arrival in
endemic areas and present approximately one to two weeks after arrival, watery
diarrhea, which may change to stereorrhea and foul-smelling lyenteric stools,
nausea, abdominal distension with pain , vomiting and occasionally weight loss.
A characteristic of travelers' diarrhea due to Giardia is that it lasts two to four
weeks and is accompanied by weight loss in more than half of the cases. In these
cases, the parasites must be confirmed by coprological examination, since there
are other causes that produce traveler's diarrhea. This acute form occasionally
occurs in endemic areas, mainly in children.
 Chronic Giardiasis:
approximately 30% to 50% of symptomatic cases become chronic. In these cases, the
diarrhea persists for a longer time or there are loose stools, abdominal pain, nausea,
vomiting, flatulence, weight loss, malaise, fatigue and nutritional deficiencies in
children, with adverse effects on growth. Malabsorption of carbohydrates, fats, vitamins
and protein loss is observed, which contributes to malnutrition and anemia. It has been
proven that this chronic form of giardiasis is more intense in patients from developed
countries. Children in endemic areas rarely or never have these features of the disease.
CLINICAL
MANIFESTATIONS

7. It is not possible to make an accurate clinical diagnosis, therefore it is necessary to
identify the parasite or its antigens. Trophozoites can be found in duodenal fluid or
diarrheal feces and cysts in solid fecal matter.
 Parasites in feces: identification of cysts in saline or lugol's solution is the most
common finding in pasty or hard stools.
 Parasites in duodenal fluid: This procedure requires fasting for more than four
hours and its sensitivity is not higher than 50%. Microscopic study of duodenal
fluid obtained by catheterization to identify Giardia.
 Antibodies in serum: it can be identified in IgM antibodies in current infections,
although it is not used as a routine diagnostic procedure.
 Other procedures: intestinal tissue biopsy, PCR and genetic probes.
1.1. EPIDEMIOLOGY AND PREVENTION
Giardiasis is transmitted by ingestion of the cysts, which are infective as soon as they are
passed in the stool. Its dissemination is done by four mechanisms.
 Transmission from person to person: Through contaminated hands.
 Waterborne: by streams in the countryside, tanks and rural aqueducts
contaminated, mainly by the waters that drag fecal matter from the earth.
 Foodbornes: Food handlers infected by this parasite can infect them through
hands or raw food.
1.2. Transmission through animal reservoirs. Transmission by beavers that live in and
pollute the water has been proven.
DIAGNOSIS

8. 5-Nitroimidazoles.
Secnidazole.
Tinidazole.
Ordinazole.
Metrodinazole.
TREATMENT

9. 1. Giardia lamblia is a bilaterally symmetrical flagellated protozoan parasite of the
intestine
thin throughout its vegetative state, the trophozoites, presenting a shape
resistant and infective, the cyst, which is transmitted in various ways, the most
Often through food.
2. Presents a suction disc, which when present in the duodenum in large quantities,
produces alteration in the mucosa.
3. It is distributed worldwide, that is, it is cosmopolitan, having a greater presence in the
Developing countries.
4. It is the species that is most frequently found in stool tests.
CONCLUSIONS