LAB (21, 12, 15)

• Nationally Notifiable Parasitic Diseases

  Cryptosporidiosis

  Cyclosporiasis

  Giardiasis

  Malaria

  Trichinellosis
• PARASITOLOGY

  branch of microbiology and is the scientific study of parasites
• PARASITISM


  symbiotic relationship that benefits one party or symbiont (parasite) and is detrimental to the other party (host).
• PARASITES

  organisms that live on or in other living organisms (hosts), at whose expenses they gain some advantage
• ECTOPARASITES


  those that live on the outside of host’s body.
• ENDOPARASITES


  live inside the host
• Parasites may involve one or more hosts, if there are more than one host involved then they are either: Definitive or Intermediate Host
• DEFINITIVE HOST


  host that harbours the adult or sexual stage of the parasite
• INTERMEDIATE HOST


  harbours the larval or asexual stage
• FACULTATIVE PARASITE

  • organism that can be parasitic, but does not have to live as a parasite
  • Capable of an independent life
• OBLIGATE PARASITE 

  those that have no choice and must inhabit hosts

  Most of the parasites that infect humans.
• HOW PARASITES CAUSE DISEASE:

  •  Varies from one species of parasite to another, and often depends on the number of parasites that are present.
  • Some produce toxins, harmful enzymes, some invasive and migratory parasites cause physical damage to tissues and organs
  • Sometimes, the host immune response to the parasites causes more injury than do the parasites themselves.
• PARASITIC PROTOZOA

  • most protozoa are unicellular
• o   Amebae move by pseudopodia (false feet)

  o   Flagellates move by flagella

  o   Ciliates move by means of cilia

  o   Sporozoans do NOT move
• -       Not all protozoa are parasitic
• -       Protozoal infections are most often diagnosed by microscopic examination of body fluids, tissue specimens, or feces – specimens are examined for motile trophozoites and dormant cyst stages.
• SKIN INFECTION

  Leishmaniasis
• LEISHMANIASIS


  caused by Leishmania genus and usually infected by an infected fly

  • has three forms: Cutaneous, Mucocutaneous, Visceral
• Cutaneous and mucocutaneous leishmaniasis can cause severe tissue damage and disfigurement.
• Visceral leishmaniasis can lead to death
• EYE PROTOZOAL INFECTION

  AMEBIC CONJUNCTIVITIS & KERATOCONJUNCTIVITIS

  TOXOPLASMOSIS
• AMEBIC CONJUNCTIVITIS & KERATOCONJUNCTIVITIS


  caused by Acanthamoeba spp.

  • can lead to loss of vision or enucleation
• TOXOPLASMOSIS


  caused by Toxoplasma gondii

  • Acquired by ingesting cysts or oocysts
• GI TRACT INFECTION

  AMEBIASIS

  BALANTIDIASIS

  CRYPTOSPORIDIOSIS

  CYCLOSPORIASIS

  GIARDIASIS
• AMEBIASIS


  caused by Entamoeba histolyca

  • MOT: humans; fecally contaminated food or water.
• BALANTIDIASIS


  caused Balantidium coli

  • MOT: pigs; food or water contaminated pig feces
• CRYPTOSPORIDIOSIS


  caused by Cryptosporidium parvum

  • MOT: infected humans, cattle, and other domesticated animals
• CYCLOSPORIASIS


  caused by Cyclospora cayentanensis

  • MOT: fecally contaminated water
• GIARDIASIS


  caused by Giardia lamblia

  MOT: humans and infected animals
• THREE PROTOZOAL INFECTIONS OF GI TRACT:

  Entamoeba histolyca

  Cryptosporidium parvum

  Giardia lamblia­
• Entamoeba histolyca

  • infects colon with secondary infection of liver
  • Infected patients pass non-infectious trophozoites as well as infectious cysts in stools.
  • Diagnosis by presence of characteristics cysts in stools
  • THERAPY: Iodoquinol and metronidazole
• Cryptosporidium parvum

  •  infects lower small intestine
  • Organisms are intracellular parasites in epithelial cells of intestinal villi
  • Diagnosis by modified acid-fast stain of stool sample
  • THERAPY: Paromomycin (often not effective)
• Giardia lamblia­

  infection usually results from drinking contaminated water.

  o   Infects duodenum, with incubation time of ten days

  o   Acute infection shows sudden onset with foul smelling, watery diarrhea

  o   Diagnosis by presence of cysts or trophozoites in stools

  o   THERAPY: Metronidazole
• GU TRACT INFECTION

  TRICHOMONIASIS

  T.VAGINALIS VAGINITIS
• TRICHOMONIASIS

  • caused by Trichomonas vaginalis, a flagellate
  • Type of STD
  • Usually asymptomatic in men and symptomatic in women
• T. VAGINALIS VAGINITIS


  usually diagnosed by observation of motile trophozoites in saline wet mount of vaginal discharge material and nucleic acid amplification tests (NAAT).
• CIRCULATORY SYSTEM INFECTION

  AFRICAN TRYPANOSOMIASIS

  AMERICAN TRYPANOSOMIASIS (CHAGAS DISEASE)

  BABESIOSIS

  MALARIA
• AFRICAN TRYPANOSOMIASIS

  • caused by Trypanosoma brucei
  • By bite of infected tsetse fly
• AMERICAN TRYPANOSOMIASIS (CHAGAS DISEASE)


  caused by T.cruzi and can be acquired through reduvid bug/triatome/kissing/cone-nosed bug
• BABESIOSIS


  caused by Babesia microti and other Babesia spp through tick bite