Lynne S. Garcia

Classification of Human Parasites, Vectors, and Similar Organisms

* Entamoeba histolytica is being used to designate pathogenic zymodemes, while E. dispar is now being used to designate nonpathogenic zymodemes. However, unless trophozoites containing ingested red blood cells (E. histolytica) are seen, the two organisms can not be differentiated on the basis of morphology. t Although some individuals have changed the species designation for the genus Giardia to G. intestinalis or G. duodenalis, there is no general agreement. Therefore, for this listing, we will retain the name Giardia lamblia. I Genetic characterization studies now suggest that because S. intestinalis is so closely related to Encephalitozoon cuniculi, it might be reclassified as Encephalitozoon intestinalis.

Classification of human parasites

Plasmodium falciparum Amebae (Intestinal) Babesia species Entamoeba histolytica Flagellates (Leishmaniae, Trypanosomes) Entamoeba dispar* Leishmania tropica complex Entamoeba hartmanni Leishmania mexicana complex Entamoeba coli ~Entamoeba cc~~oll~~i ~Leishmania braziliensis complex Entamoeba polecki Endtamoeba poleki Leishmania donovani complex Endolimax nana lodamoeba buitschlii Leishmania peruviana Blastocystis hominis Trypanosoma brucei gambiense Trypanosoma brucei rhodesiense Flagellates (Intestinal) Trypanosoma cruzi Giardia lambliat Trypanosoma rangeli Chilomastix mesnili

Blood parasites: Problems in diagnosis using automated differential instrumentation

To examine potential problems inherent in using automated differential instruments, we have reviewed herein two cases where blood parasites, Plasmodium vivax and Plasmodium falciparum, were completely missed by use of this method. Diagnosis of these infections was made when blood was sent to the parasitology laboratory after having been missed prior to that time. The first problem involved the laboratory request slip; no indication was made concerning possible suspect organisms. Therefore, peripheral blood examinations were performed using automated equipment. The number of fields scanned by a technologist on these smears is quite low; thus failure to pick up a light parasitemia is almost guaranteed. In both cases, after diagnosis had been made on smears submitted to the parasitology division, all previous smears examined by the automated system were reviewed and found to be positive for parasites. Failure to make the diagnosis resulted in delayed therapy. Although these instruments are not designed to detect intracellular blood parasites, the inability of the automated systems to discriminate between uninfected red blood cells and those infected with parasites may pose serious diagnostic problems.

Cryptosporidiosis: A continuing challenge for the clinical and public health microbiologist: Strategies for proactive detection of waterborne cryptosporidiosis by clinical and public health microbiology laboratories

Abstract Laboratories have a key role in the early detection of outbreaks of cryptosporidiosis and other community-acquired intestinal diseases. This can be accomplished by monitoring the increases in the number of stool specimens, prompt recognition of the etiologic agent, networking with other laboratories, and follow-up with appropriate public health agencies. By following these critical steps, strategies for outbreak intervention can be implemented and potential outbreaks curtailed.

Special laboratory examinations for parasitic infections

Besides the routine procedures used for the diagnosis of parasites, there are a number of other diagnostic techniques available for the recovery and identification of parasites. Most laboratories do not routinely offer all of these techniques, but many are relatively simple and inexpensive to perform. This article discusses these techniques and their clinical relevance.