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3.1.2.1 Trophozoite
Literally means any stage in the life cycle of a protozoan which can ingest food. In practic
3.1.2.2 Cyst
Is the non-motile form, which is protected by a distinct membrane or a cyst wall. This is the infective stage of the parasite with the exception of Dientamoeba fragilis and Entamoeba gingivalis
3.1.2.3 Pre-Cyst
Is the process of emergence of the trophozoite from the cyst.
Is the process of formation of the cyst from the trophozoite.
Is the trophozoite which emerges from the cyst.
Is the external hyaline portion of th cytoplasm which is generally visible in a moving trophozoite.
Is the internal granular portion of the cytoplasm which contains various food inclusions.
Is the RNA-protein complex which stains deeply with basic dyes but not with iodine. It is found in the genus Entamoeba. In the electron microscope it reveals a crystalline structure resembling virus particles.
Is a glycogen reserve which stains deeoply with iodine and is found mainly in the cysts.
Literally means false foot. It refers to temporary cytoplasmic processes formed at the surface of the trophozoite.
A membrane bound vesicle in the cytoplasm formed around an ingested food particle.
A membrane bound vesicle in the cytoplasm which collects and expels water from the cell. This is found in the free-living amoebae.
Is the substaince in the cell nucleus which stains with basic dyes.
Amoebae parasitic to both vertebrates and invertebrates. Several species infect man and domestic animals; Entamoeba histolytica is the most important.
3.1.3.1.1 Classification
- 1. Phylum Sarcomastigophora
- 2. Family Emta,penodae
- 3. Characteristics of genus Entamoeba
- a. Vesicular nucleus
- b. Endosome which is located at or near center of nucleus
- c. All have trophozoite and cyst stages in their life cycle.
- d. Cysts may or may not contain chromatoid bodies.
- 4. Entamoeba histolytica causes intestinal and extra intestinal amoebiasis. The parasite has been described from man, many subhuman primates, dogs, cats, pigs, rats and perhaps cattle.
3.1.3.1.2 Geographic Distribution: worldwide
3.1.3.1.3 Epidemiology
- 1. E. histolytica is contracted by ingestion of cysts.
- 2. Cysts are resistant to water chlorination, but are rapidly destroyed by drying or deep freezing.
- 3. Cysts are rendered noninfectious by heating to 500 C for 5 minutes.
- 4. Usual method of transmission is fecal-oral contamination, usually of uncooked food such as salads and vegetables.
- 5. Cysts may pass unharmed through the gut of housefiles and cockroaches.
3.1.3.1.4 Life cycle
Terminology and Morphology of the different stages.
3.1.3.1.4.1 Trophozites
1. Trophozoites (Fig 2.1.A) are amoeboiid and range in size from 15 to 50 diameter.
- a. Nucleus contains a centrally located endosome (Karyosome)
- b. Chromatin is ver fine and is distributed at periphery of the nucleus.
- c. cytoplasm may contain food vacuoles filled with ingested RBC's
3.1.3.1.4.2 Pre-Cyst
2. The pre-cyst stage (Fig 2.1.B) occurs as an intermediate between the trophozoite and the true cyst.
3.1.3.1.4.3 Cyst
3. Cyst (Fig 2.1.C) is the infective stage. It is smaller than the trophozoite (10-20 um in diameter). Four nuclei are present in mature cysts.
3.1.3.1.4.4 Life Cycle
4. Life Cycle (Figures 2.2, 2.3 and 2.4)
After ingestion of the cyst, the cyst wall is digested in the small intestine with release of 4 motile, amoeboid trophozoites. The trophozoites take up residence in the crypts of the cecum and large intestine, bathed by bacteria-laden fluid medium necessary for their survival. As intestinal contents become more solid, the parasite enters the precystic stage, followed by encystment. Trophozoites divide by binary fission in cecum and colon. Establishment of intestinal infection may be followed by encystment. Trophozoites divide by binary fission in cecum and colon. Establishment of intestinal infection may be followed by invasion of other organs including liver, lung and brain.
Figure 2.2: Life Cycle Entamoeba Spp.
Figure 2.3: Life Cycle Entamoeba
Figure 2.2: Life Cycle Entamoeba
3.1.3.1.4.5 Pathology and Pathogenicity
- 1. Only certain strains of E. histolytica are pathogenic.
- 2. Lesions occur when trophozoites invade the cecal, colonic or rectal mucosa. The ulcers are flask-shaped.
- 3. Liver lesions
- a. Abscesses are usually singular.
- b. Right lobe most commonly affected.
- c. Males more commonly affected than females.
- d. Contents of abscesses are purulent, necrotic, sterile and odorless.
- 4. Lungs may become infected either by extension through the diaphragm or via hematogenous route.
- 5. Abscesses may occur brain if trophozoites pass to the brain via the blood.
- 6. Clinical Aspects
a. Intestinal amoebiasis
- 1. abdominal discomfort
- 2. flatulence
- 3. recurring diarrhea and constipation
- 4. tenderness in abdomen
- 5. blood and mucus may be found in stools
- 6. frequent tenesmus
- 7. patient may be febrile
b. Liver
- 1. pain in hepatic region
- 2. jaundice may be prsent
- 3. edema of skin
c. CNS
- 1. Usually fatal due to late diagnosis
3.1.3.1.4.6 Diagnosis (Figure 2.5)
- 1. Cysts are usually seen in formed stools
- a. Zinc sulfate floatation/iodine stain
- 2. Trophozoites are usually seen in diarrheic stools -stools should be examined shortly after passage
- a. Direct smear (saline mount)
- b. Direct smear stained with trichrome or iron-hematozylin
- 3. At least three specimens of stool should be examined, preferably at weekly intervals. Is may be helpful to examine the stool after administering a prugative.
Fig 2.5: Diagnosis
- 4. Serology
- a. Only of value in confirming diagnosis of invasive lesion
- 1. IHA
- 2. Agar gel immunodifussion
- 3. IFAT
- 5. Charcot-Leyden crystals
- a. Six-sided crystals often observed in the feces of persons with parasitic infections. They are thought to be breakdown products of eosinophils.
- 6. Sigmoidoscopy
- 7. Radiologic examination
In summary, the following characteristics are of value in the identification of Entamoeba histolytica (figure 2.6):
I. Trophozoites
SUGGESTIVE:
- (a) progressive motility
- (b) hualine unstained pseudopodia
- (c) no ingested bacteria,
- (d) nuclei not visible
3.1.3.1.4.6 DIAGNOSTIC
Ingestion of red blood cells.
II. Trophozoites
SUGGESTIVE:
- (a) clear differentiation of ectoplasm and endoplasm
- (b) no ingested bacteria.
DIAGNOSTIC
- (a) fine uniform granules of peripheral chromatin and small central kayosome in nucleus
- (b) ingested red blood cells
- (c) average size over 12 p.m.
III. Cysts, unstained
SUGGESTIVE:
- (a) nuclei
- (b) rod-like chromatoidals
IV. Cysts, stained
SUGGESTIVE
- (a) maximum of four nuclei having both karyosome and peripheral chromatin
- (b) diameter over 10 p.m.
DIAGNOSTIC
- (a) typical nuclear structure
- (b) chromatoidal bars with rounded or squared ends
- (c) diameter over 10 p.m
Fig 2.6: Identifying Characteristics of Enamoeba SPP.
Entamoeba histolytica:
1. Trophozoite with hyaline pseudopodium; 4, trophozoite containing red blood cells; 5, early cyst containing glycogen mass and chromatoidals; 8, mature 4-nucleate cyst with chromatoidals.
Entamoeba hartman ni: 2,3 trophozoites; 6, 7, uninucleate cysts.
3.1.3.1.4.7 Treatment
1. Intestinal Amoebiasis
- a. Metrondiazole (flagyl) 800 mg TID for 10 days
- b. Tinidazole 2 g SID for 5 days (not approved for use in U.S)
- c. Diloxanide furoate (Furamid) should be used as a follow-up to either of the above regimens at 500 mg TID for 10 days.
2. Extra-intestinal amoebiasis
- a. Metronidazole (Flagyl) 2 g daily for 5 or more days
3.1.3.2.1 Entamoeba Coli
- A. Entamoeba coli is a common inhabitant of the lumen of the cecum and colon of man and other animals. It is non-pathogenic, though its trophozoites and cysts must be differentiated from those of E. histolytica.
3.1.3.2.2 Entamoeba gingivatis
- B. Entamoeba gingivalis is a common inhabitant of the mouth of man. It is nonpathogenic and does not form cysts.
3.1.3.2.3 Entamoeba species of domestic animals
- 1. Entamoeba equi
- 2. Entamoeba gallinarum
- 3. Entamoeba bovis
- 4. Entamoeba ovis
- 5. Entamoeba suis
- 6. Entamoeba caprae
3.1.3.2.4 Endolimax nana
- D. Endolimax nana is a common inhabitant of the cecum and colon of man and other primates, and of pigs. It is nonpathogenic.
3.1.3.2.5 Iodoamoeba buetschlii
- E. Iodoamoeba buetschlii is a common inhabitant of the cecum and colon of man and other primates, and of pigs. It is usually nonpathogenic.
3.1.3.2.6 Dientamoeba fragilis
- F. Dientamoeba fragilis is believed by some to be nonpathogenic - others attribute gastrointestinal symptoms to its presence. Some workers believe it is a flagellate.
Table 3.1: Differential characteristics of intestinal amoebae (live specimens)
-
E. histolytica
E. hartmanni
E. coli
E. polecki
E.nana
l. butschlii
D.fragilis*
ITraphozoiteMovement
Active especially in acute dysentery
Sluggish
Sluggish
sluggish
Sluggish
Active
Active often multiple pseudopods
Inclusions
Red cell in case of tissue invasion
No red cells
No red cells
No red cell
No red cell
No red cell
No red cell
Table 3.2: Differential characteristics of intestinal amoebae (stained specimens)
-
E. histolytica
E. hartmanni
E. coli
E. polecki
E. nana
I.butschlii
D.fragilis
TrophozoiteNo. of nuclei
1
1
1
1
1
1
2
Karysome(Nucleolus)
Usually central small
Usually central small
Usually central small
Usually central small
Large
Large generally irregular
Large may be fragmented
Peripheral chromatin
Usually symmetrical fine
Usually symmetrical fine
Usually symmetrical fine
Usually symmetrical fine
Usually symmetrical fine
Incon-spicuous
Incon-spicuous
Cyst No. nuclei
4
4
8
1
1
1
Cysts not found
Shape
Circular
Circular
Circular
Circular
Usually oval
Irregular
-
Size(dia.)
12-20 um
2-8 um
15-25 um
11-15 um
8-12 um
10-16 um
-
Chromatoid body
Usually large rounded ends
Usually large rounded ends
Usually small splintered ends
Variable shape
Absent
Absent
-
Glycogen vacuole
Diffuse
Diffuse
Diffuse
Diffuse
Absent
large and sharply demarcated -
Other inclusions
Nil
Nil
Nil
Usually large faintly staining mass
Nil
Some times minute rod like bodies
-
Free-living amoebae of the genera Naegleria ad Acanthamoeba that now are known to cause disease in man and other animals. Infections of the CNS due to Hartmanella spp. are now thought to have been caused by Acanthamoeba spp.
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3.1.4.2.6 Pathology and Pathogenicity
- 1. Primry amoebic meningoencephalitis (PAM)
- a. Acute disease
- b. Symptoms similar to bacterial meningitis
- c. Indications of Naelgeria infection is elevated white cell count in CSF without the successful recovery of bacteria.
- d. At necropsy, olfactory bulb is inflamed and necrotic
- e. Masses of amoeba may be seen histopathologically in the brain, especially near the subarachnoid space
- f. Amoebae are not normally found outside the brain or nasopharynx.
- 2. Acanthamoeba in humans
- a. Disease due to this species is more variable
- 1. This species apparently enters wonds
- 2. Clinical course is not as acute
- 3. Most cases PAM are granulomatous encephalitides in which amoebae resembling Acanthamoeba were recovered from the CSF or from the granuloma or abscess-like lesion.
- 4. Acanthamoeba spp. are thought to infect other sites in te body (Intestine, Cornea)
3.1.4.2.7 Diagnosis
- 1. Recovery of amoebae from CSF or from lesions
- 2. Serology
- a. CF for Acanthamoeba
3.1.4.2.8 Treatment
- 1. Naegleria spp.
- a. Amphotericin B
- b. Clotremizole
- 2. Acanthamoeba spp.
- a. Sulfadiazine has been used successfully in experimental animals.
PHYLUM SARCOMASTIGOPHORA
3.2.2.1 Kinetoplast:
An oval or rod-shaped body seen in hemoflagellates. It stains with nuclear dyes and contains DNA. It is regarded as a modified part of the mitochondrium.
3.2.2.2 Flagellum:
An elongated hair-like organelle used for locomotion. At ultrastructure level it reveals one pair of central tubules and nine pairs of peripheral tubules.
3.2.2.3 Pleomorphic:
When a number of morphological types occurin 1 life cycle
3.2.2.4 Monomorphic:
When only a single morphological type occurs in 1 life cycle.
3.2.2.5 Metacyclic trypanosome:
Infective forms of trypanosomes which develop in the vector.
3.2.2.6 Xenodiagnosis:
A method of diagnosis in which a vector is fed on a suspected case and later examined for presence of the parasite.
3.2.2.7 Haemocoele:
The body cavity of arthropods.
3.2.2.8 Peritrophic membrane:
A membrane which is secreted from the anterior end of the midgut in some blood-feeding arthropods. This membrane encloses the blood meal.
3.2.2.9 Stercorian trypanosome:
Infective forms which develop in the feces of the insect vector and enter the vertebrate host by the contamination of the bite area. This is also known as the posterior station development.
3.2.2.10 Salivarian trypanosome:
Infective forms which develop in the mouth parts or salivary glands and enter the vertebrate host by inoculation during the act of biting. This is also known as the anterior station development.
3.2.2.11 Undulating membrane:
Is a membranous structure which connects the flagellum to the body of the parasite. It is thrown into folds as the parasite moves, giving itan undulating appearance.
3.2.2.12 Costa:
A cytoplasmic thickening seen at the base of the undulating membrane in some flagellates.
3.2.2.13 Axostyle:
A central supporting rod seen in some flagellates.
3.2.2.14 Amastigote:
Alos known as the "leishmanial" stage. It is round or oval in shape without any free flagellum.
3.2.2.15 Promastigote:
Also known as the "leptomonad" stage. It is elongated with the kinetoplast anterior and distal to the nucleus. The flagellum emerges from the anterior end. There is no undulating membrane.
3.2.2.16 Epimastigote:
Also known as the "crithidial" stage. It is elongated with the kinetoplast posterior and distal to the nucleus. There is a short undulating membrane.
3.2.2.17 Trypomastigote:
Alsoknown as the "trypansome" stage. It is elongated with the kinetoplast posterior and distal to the nucleus. There is a long undulating membrane.
3.2.2.18 Axoneme:
A delicate filament extending from the region of the kinetoplast to the cell membrane. It represents the cytoplasmic part of the flagellum.
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3.2.3.2.1 Morphology
The body is piriform with two nuclei near the anterior end, six anterior and two posterior flagella, and two independent axostyle. The body is quite symmetrical.
3.2.3.2.2 Species of importance.
1 . H. Meleagridis
- a.Hosts Turkeys, peafowls, quail, Pheasants - Tran-missible to other Avian species.
- b.Location: Duodenum, small intestine of young birds -adult birds are symptomless carriers
- c. Transmission is by fecal contamination of fecal and water.
- d. Pathogenicity:
- disease state or losses seldom occur in birds over ten weeks.
- e. Pathology:
- Catarrhal enteritis; foamy, watery diarrhea; loose wt rapidly; become restless weak and
- finally die- mortality is high in recovered birds.
- f. Diognosis:
- by finding organism in intestinal scrapings mixed with saline
- g. Prevention:
- Proper sanitation and management; Separate poults from adults; use separate caretakers;sell breeding birds before any adults are hatched.
2. Other Species
- a. H. Columbae -Pigeon
- b. H. Muris -Rat, Mouse
- c. H. Pitheci - Rhesus Monkeys
3.2.3.3.1 Morphology
The organism is somewhat pleomorphic in that its morphology depends upon the organ location and the stage of the disease. The stage which occurs in the lumen of the intestine is 5-30 microns in diameter, amoeboid, has a clear ectoplasm, and a granular endoplasm. The nucleus is vesicular and a flagellum arises from a small blepharoplast near the nucleus. Occasionally two flagella may be present. In the tissues, the organism is found singly or in clusters and is 8-15 microns in diameter, is amoeboid, and has no flagella.
3.2.3.3.2 B. Hosts:
Turkeys, chicken, peafowl, guinea fowl, pheasant, partridge, and quail.
3.2.3.3.3 Location:
The organism is found in the ceca and liver of the turkey and is the cause of histomoniasiss, infectious enterohepatitis, or blackhead.
3.2.3.3.4 Transmission:
The main route of infection is by the ingestion of the embryonated eggs of the cecal worm Heterakis gallinarum.
3.2.3.3.5 Life Cycle:
The life cycle of H. meleagridis is complex. Free trophozoites passed in feces are very delicate and essentially have no role in transmission. Trophozoites within eggs of the roundworm Heterakis gallinarym are readily infective to other birds. Usually heterakid eggs are ingested by earthworms, and birds become infected with both the roundworms and the flagellates after ingesting suc earthworms. In the avian intestine, the trophozoite is released from the roundworm egg and invades cecal wall. It loses its flagellum and becomes very pleomorphic and amoeboid. It often migrates to the liver (See figure 2.11).
3.2.3.3.6 Pathology:
H. meleagridis causes enlarged, rather hemorrhagic ceca and characteristic, depressed liver lesions. In tissues, trophozites occur in clusters. They vary in size and shape and are poorly stained with H&E but stain brilliantly with PAS. A few birds may show a darkened or cyanotic discoloration of the skin of the head and wattles from which the name 'blackhead' arises.
Figure 2.11: Life Cycle of Histomonas
G. Diagnosis:
Histological examination of stained sections of the liver show necrosis and colonies of organisms.
H. Prevention:
Good husbandary and preventive medication.
3.2.3.4.1 Classification
- 1. Trichmonads are flagellates belonging to the protozoan family Trichomonadidae.
- 2. They are a heterogeneous assemblage of organisms that re adapted to live in an anaerobic habitat. Some cause disease in man or domestic animals, but most do not. They have been found in practically every species of mammal or bird and also in fish, amphibia, reptiles and many invertebrates.
3.2.3.4.2 Characteristics of trichomonads
- 1. Body is usually piriform-rounded anterior end, pointed posterior end.
- 2. Single nucleus in anterior portion of body.
- 3. Three to 5 anterior flagella and a posterior or recurrent flagellum.
- 4. Undulating membrane.
- 5. Pelta - sheet of microtubules that functions in support.
- 6. Axostyle - simple or multilayered ribbons of microtubles that function as internal cyto-skeleton.
- 7. Parabasal body - Trichomonad golgi apparatus.
- 8. Blepharoplast - basal body; centriole-like structure from which the flagellum arises.
- 9. Costa - unique to trichomonads - support for undulating membrane?
- 10. All divide by longitudinal fission and have no cyst stage.
- 11. The morphologic characteristics are illustrated in Figure 2.12.
3.2.3.4.3. T. Vaginalis
1. Morphology
- a. T. Vaginalis has a single nucleus and divides by binary fission
- b. It ingests food particles through a cytostome found at the anterior end.
Fig 2.12: Morphological Features of Trichomonas
2. Clinical aspects
- a. In the female, trichomoniasis can give rise to vaginitis resulting in a frothy and creamy white discharge. The vulva and cervix may be inflamed.
- b. The majority of males remain asymptomatic, but in some, urethritis and prostatitis may occur.
3. Diagnosis
Diagnosis is easily made by observing the parasite in the vaginal secretion or, in the case of the male, in the semen (Hoffman et al., 1961) . The parasite can also be grown in artificial media.
4. Life Cycle
Life Cycle of Trichomonas vaginalis (see figure 2.13)
In the majority of cases the parasite is transmitted during sexual intercourse, the male acting as a carrier. Cysts are not formed during the life cycle.
Fig 2.13:Life Cycle of T. Vaginalis
5. Related genera
- a. tritricomonas fetus*
- b. Histomonas meleagridis*
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3.2.3.5.1 Classification
- A. All trypanosomes belong to the famioy Trypanosomatidae
- 1. Most are heteroxenous
- 2. All are hemoflagellates
- B. Strecorarian trypanosomes (strecos = feces)
- 1. Develop in posterior part of a alimentary tract of intermediate host (posterior station)
- a. Trypanosoma cruzi - man
- b. T. rangeli - man
- c. T. lewisi - rats
- C. Salivarian trypanosomes
- 1. Develop anteriorly in the intermediate host; injected by the proboscis from the salivary glands
- a. Trypanosoma brucei brucei livestock - Nagana
- b. T. brucei gambiense man live stock
- c. T. brucei rhodensiense man livestock
- d. T. evansi - equine
- e. T. equinum
- f. T. congolense
- D. Trypansoma equiperdum (Equine syphyllis) - transmitted by coitus
3.2.3.5.2 Morphology
- A. Trypanosomes are pleomorphic. All have one or more of the following morphologic forms in their developmental cycle. The name of each morphologic form is based on the presence or absence of flagellum. If the flagellum is present, the name indicates it position relative to the nucleus. (See figure 2.14)
- B. Flagellum originates from basal body, a centrosome-like structure
- C. Kinetoplast - adjacent to basal body; extension of mitochondrion
- D. Undulating membrane - this is actually not a membrane but consists of the flagellum and that portion of the parasite cell to which it is attached - trypomastigote and epimastigote
Fig 2.14: Morphology of Trypanosomes
3.2.3.5.3.1. African trypanosomiases (African sleeping sickness, Gambien trypanosomiasis, Rhodesian)
- 1. Infection in man caused T. brucei gambiense or T. brucei rhodesiense. Native game animals are reservior of T. brucei rhodesiense but nto T. brucei gambiense.
- 2. Geographic distribution - tropical Africa
- T. brucei gambiense occurs in west and central Africa;
- T. brucei rhodesiense occurs in ease Africa.
- 3. Epidemiology
Fig 2.15 :T. brucei is transmitted to the mammalian host by tsetse flies ( see figure.2.15)
3.2.3.5.3.2 . American Trypanosomiasis (Changas' disease)
- 1. Infection in man caused by the protozoan Trypanosoma cruzi.
- a. Reservoir hosts are marsupials, edentates, bats, rodents, carnivores, pigs, primates.
- 2. Geographic distribution
- a. T. cruzi is present in all Central and South American countries. Infected bugs and mammals have been found as far north as northern California and Maryland (See figure 2.16).
- 3. Epidemiology
- a. The intermediate hosts for T. cruzi are bugs of the family Reduviidae (kissing bugs). Principle genera are Triatoma, Rhodnius and Panstronglylus.
Fig 2.16: Geographic Distribution of T. Cruzi
- b. kissing bugs feed principally around the mouth and eyes by may feed at any exposed site. The bugs defecate as they take the blood meal. Infective trypanosome in feces then enter the bite wound actively or passively when the victim scratches the irritating wound (see fig 2.17)
- 4. Morphology
- a. In the blood, T. cruzi is monomorphic, 16-20 microns in length, and crescent-shaped with a pointed posterior end.
- b. The kinetoplast is large and subterminal.
- c. the nucleus is midway along the body and there is a moderately well developed undulating membrane and free flagellum.
- 5. Life Cycle
- a. Metacyclic trypanosomes are passed in the feces of infected bugs 8-10 or more days after initial infection.
Figure 2.17: Transmission of T. Cruzi
- b. Following introduction into the mammalian host, the metacyclic trypanosomes undergo development as illustrated in Fig 2.18
- 6. Clinical Manifestations
The disease in man may be acute or chronic. Death may occur in 2-4 weeks after the onset of symptoms in acute cases or they may resolve to the chronic form of the infection. The acute form usually occurs in infants and young children while the chronic form is generally manifested in adults. The clinical manifestations depend on the location of the organisms but the cardiac form is common. Death may be due to cardiac arrhythmia or to slow loss of cardiac function.
Fig 2.18 : Metacyclic Trypanosomes undergo development Life Cycle of T. Cruxi
- In dogs, debility, anemia, and splenomegaly occur, young animals being especially susceptible. Myocardial involvement also occurs in dogs but it is not as extensive as in man.
- In cats, convulsions and posterior paralysis may be seen.
1. Heart
- a). Principle gross observation is enlargement and dilatation.
2. CNS
- a) Principle gross observation are changes characteris- tic of meningomyeloencephalitis.
3. Cellular infiltrates
- a) Consist primarily of lymphocytes, macrophages, and plasma cells
1. Heart
- 1Focal areas contain infiltrates of lymphocytes and plasma cells and streaks or patches of interstitial fibrosis among hypertrophied myofibers.
- 2. Other Organs Colon (Esophagus, Bronchi, ureters, duodenum and stomach)
- a) Dilatation
Leishmania spp. are transmitted by flies of the genus phlebotomus in the old world and Lutzomyia in the new world (see figure 2.19)
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