Diagnostic Medical Parasitology, Sixth Edition

With the expansion of world travel and increased access to more varied geographic areas and populations, medical and laboratory professionals will continue to see more “tropical” diseases and infections in nonendemic areas. This is due to the rapidity with which both people and organisms can be conveyed from one place to another. Travel has become available and more affordable for many people throughout the world, including those who are in some way compromised in terms of their overall health status. The increased transportation of infectious agents, as well as potential human carriers, has been clearly demonstrated, particularly via air travel. It has also been well documented that vectors carrying parasitic organisms can be transported via air travel in baggage and in the unpressurized parts of the plane itself; once released, these infected vectors can then transmit these parasites to humans, even in nonendemic areas.

• Safety
• Fresh-specimen collection
  • Collection of the specimen
  • Number of specimens to be collected (standard recommendation)
  • Number of specimens to be collected (pros and cons of various options)
  • Collection times
  • Specimen type, specimen stability, and need for preservation
• Preservation of specimens
  • Preservatives
    • Formalin
    • MIF
    • SAF
    • Schaudinn's fluid
    • Schaudinn's fluid containing PVA (mercury base)
    • Schaudinn's fluid containing PVA (copper base, zinc base)
    • Single-vial collection systems (other than SAF)
    • Universal Fixative (TOTAL-FIX)
  • Use of fixatives
    • Quality control for stool fixatives
    • Procedure notes for use of preservatives
    • Procedure limitations for use of preservatives
• Shipment of diagnostic specimens, biological products, etiologic agents, or infectious substances
  • Documentation

• Macroscopic Examination
• Microscopic Examination (Ova and Parasite Examination)
  • Direct wet smear
  • Concentration (sedimentation and flotation)
  • Permanent stained smear
• Specialized Stains for Coccidia (Cryptosporidium, Cystoisospora [Isospora], and Cyclospora Species) and the Microsporidia
  • Modified Kinyoun's acid-fast stain (cold method)
  • Modified Ziehl-Neelsen acid-fast stain (hot method)
  • Carbol fuchsin negative stain for Cryptosporidium (from W. L. Current)
  • Rapid safranin method for Cryptosporidium
  • Rapid safranin method for Cyclospora, using a microwave oven
  • Auramine O stain for coccidia (from Thomas Hänscheid)
  • Modified trichrome stain for the microsporidia (Weber—green)
  • Modified trichrome stain for the microsporidia (Ryan—blue)
  • Modified trichrome stain for the microsporidia (Kokoskin—hot method)
  • Acid-fast trichrome stain for Cryptosporidium and the microsporidia

• Culture of larval-stage nematodes
  • Harada-Mori filter paper strip culture
  • Filter paper/slant culture technique (petri dish)
  • Charcoal culture
  • Baermann technique
    • Modification of the Baermann method
  • Agar plate culture for Strongyloides stercoralis
• Egg studies
  • Estimation of worm burdens and Kato-Katz thick film
    • Direct-smear method of Beaver
    • Dilution egg count
    • Modified Stoll dilution method
    • Kato-Katz thick smear
  • Hatching of schistosome eggs
• Search for tapeworm scolex
• India ink injection procedure for tapeworm proglottids
• Qualitative test for fecal fat
• Quantitation of reducing substances (Clinitest)

• Examination for pinworm
  • Cellulose tape preparations
  • Anal swabs
• Sigmoidoscopy material
  • Direct saline mount
  • Permanent stained slide
• Duodenal contents
  • Duodenal drainage
  • Duodenal capsule technique (Entero-Test)
• Urogenital specimens
  • Trichomoniasis
  • Filariasis
  • Schistosomiasis

• Expectorated sputum
• Induced sputum
• Aspirates
  • Lungs and liver
  • Lymph nodes, spleen, liver, bone marrow, spinal fluid, eyes, and nasopharynx
  • Cutaneous ulcer
• Biopsy material
  • Skin
  • Lymph nodes
  • Muscle
  • Rectum and bladder

• Preparation of thick and thin blood films
  • Thick blood films
  • Thin blood films
  • Combination thick and thin blood films (on the same slide)
  • Combination thick and thin blood films (can be stained as either)
  • Buffy coat blood films
• Staining blood films
  • Giemsa stain
  • Wright's stain
  • General notes on staining procedures
• Proper examination of thin and thick blood films
  • Thin blood films
  • Thick blood films
  • Determination of parasitemia
• Diagnosis of malaria: review of alternatives to conventional microscopy
  • QBC microhematocrit centrifugation method
  • ParaSight F test
  • NOW malaria test
  • Flow anti-pLDH Plasmodium monoclonal antibodies
  • Molecular testing
  • Automated blood cell analyzers
• Diagnosis of leishmaniasis: review of alternatives to conventional microscopy
  • ICT for detection of anti-rK-39 antibodies
• Concentration procedures
  • Cytocentrifugation technique
  • Knott concentration procedure
  • Membrane filtration technique
  • Gradient centrifugation technique
  • Triple-centrifugation method for trypanosomes
• Special stain for microfilarial sheath
  • Delafield's hematoxylin

• Culture methods
  • Intestinal protozoa
  • Pathogenic free-living amebae
  • Blastocystis spp. (Blastocystis hominis)
  • Pathogenic flagellates
  • Flagellates of blood and tissue
  • Toxoplasma gondii
  • Plasmodium and Babesia spp.
  • Cryptosporidium spp.
  • Microsporidia
• Animal inoculation
  • Leishmania spp.
  • Trypanosoma spp.
  • Toxoplasma gondii
• Xenodiagnosis

• Fixation of parasite specimens and arthropods
  • Protozoa
  • Solutions to induce relaxation in adult helminths
  • Nematodes
  • Trematodes
  • Cestodes
  • Helminth eggs and larvae
  • Arthropods
• Mounting and staining of parasite specimens for examination
  • Nematodes
  • Trematodes
  • Cestodes
• Mounting of arthropods for examination
  • Mites
  • Fleas and lice
  • Ticks
  • Miscellaneous arthropods

• Protozoa
  • Amebae
  • Flagellates
  • Ciliates
• Coccidia and microsporidia
  • Cryptosporidium spp. and Cyclospora cayetanensis
  • Cystoisospora belli
  • Microsporidia
• Blood and body fluids
  • Malaria parasites and Babesia spp.
  • Leishmaniae and trypanosomes
  • Microfilariae
  • Body fluids: ciliated epithelial cells
• Helminths
  • Adult worms and larvae
  • Eggs
• Human cells
  • Polymorphonuclear leukocytes
  • Eosinophils
  • Macrophages
  • Lymphocytes
  • Red blood cells
  • Charcot-Leyden crystals
• Nonhuman elements seen in feces (yeast cells)
  • Insect larvae
  • Spurious infections
  • Delusory parasitosis (delusionary infestation)

• Equipment
  • Microscope
  • Centrifuge
  • Fume hood
  • Biological safety cabinet
  • Refrigerator-freezer
• Supplies
  • Glassware
  • Miscellaneous supplies
  • ATCC quality control organisms
• Safety: personnel and physical facilities
  • General precautions
  • Handwashing
  • Personal protective equipment (OSHA 2001 blood borne)
  • Handling specimens
  • Processing specimens
  • Spills
  • Disposal of contaminated materials
  • Standard precautions
  • Hepatitis exposure protocol
  • Dangerous properties of industrial materials
  • Current OSHA regulations for the use of formaldehyde
  • Latex allergy
• Quality systems
  • Extent of services
  • Proficiency testing
  • In-house quality control
  • Patient outcome measures
  • Continuous quality improvement, total quality management, or 10-step and FOCUS-PDCA for performance improvement activities
  • CLIA '88 inspection process
• New quality guidelines
  • ISO guidelines
  • CLSI (NCCLS) model
• Factors influencing future laboratory practice
  • Managed care
  • Financial considerations
  • Current regulations
  • Decentralized testing
  • Laboratory services
  • Technological trends
  • Clinical decision support
  • Personnel issues
  • Changing demographics
  • Emerging diseases
  • Bioterrorism

• Protozoal infections
• Helminth infections
• Blood parasite infections
• Diagnostic methods and proficiency testing

• • Ascaris lumbricoides
  • Enterobius vermicularis
  • Trichuris trichiura
  • Capillaria philippinensis
  • Hookworms (Ancylostoma duodenale, Necator americanus, and Ancylostoma ceylanicum)
  • Trichostrongylus spp.
  • Strongyloides spp.

• • Trichinella spp.
  • Baylisascaris procyonis
  • Lagochilascaris minor
  • Toxocara canis and T. cati (visceral larva migrans and ocular larva migrans)
  • Ancylostoma braziliense and A. caninum (cutaneous larva migrans)
  • Human eosinophilic enteritis
  • Dracunculus medinensis
  • Angiostrongylus (Parastrongylus) cantonensis (cerebral angiostrongyliasis)
  • Angiostrongylus (Parastrongylus) costaricensis (abdominal angiostrongyliasis)
  • Gnathostoma spinigerum
  • Gnathostoma doloresi, G. nipponicum, G. hispidum, and G. binucleatum
  • Anisakis simplex, A. physetesis, Pseudoterranova decipiens, Contracaecum osculatum, Hysterothylacium aduncum, and Porrocaecum reticulatum (larval nematodes acquired from saltwater fish)
  • Capillaria hepatica
  • Thelazia spp.

• Basic Life Cycle
• The Endosymbiont
• Human Pathogens
  • Wuchereria bancrofti
  • Brugia malayi
  • Brugia timori
  • Zoonotic Brugia infections (American brugian filariasis)
  • Tropical pulmonary eosinophilia
  • Loa loa
  • Mansonella ozzardi
  • Mansonella perstans
  • Mansonella streptocerca
  • Onchocerca volvulus
  • Dirofilaria Dirofilaria and Dirofilaria Nochtiella spp.

• • Diphyllobothrium latum
  • Taenia solium
  • Taenia saginata
  • Taenia asiatica (Asian Taenia or Taenia saginata asiatica)
  • Hymenolepis (Rodentolepis) nana
  • Hymenolepis diminuta
  • Dipylidium caninum

• • Echinococcus granulosus (cystic hydatid disease)
  • Echinococcus multilocularis (alveolar hydatid disease)
  • Echinococcus oligarthrus and Echinococcus vogeli (polycystic hydatid disease)
  • Taenia (Multiceps) spp. (Taenia multiceps, Taenia serialis) (coenurosis)
  • Spirometra mansonoides and Diphyllobothrium spp. (sparganosis)
  • NOTE Taenia solium (cysticercosis) is discussed in chapter 16.

• • Fasciolopsis buski
  • Echinostoma ilocanum
  • Heterophyes heterophyes
  • Metagonimus yokogawai
  • Gastrodiscoides hominis

• Liver Flukes
  • Clonorchis sinensis
  • Opisthorchis viverrini
  • Opisthorchis felineus
  • Fasciola hepatica
  • Fasciola gigantica
• Less Common Liver Flukes
  • Dicrocoelium dendriticum, Dicrocoelium hospes, and Eurytrema pancreaticum
• Lung Flukes
  • Paragonimus westermani
  • Paragonimus kellicotti

• • Schistosoma mansoni
  • Schistosoma japonicum
  • Schistosoma mekongi
  • Schistosoma malayensis
  • Schistosoma haematobium
  • Schistosoma intercalatum

• • Entamoeba histolytica
  • Entamoeba dispar
  • Entamoeba moshkovskii
  • Entamoeba bangladeshi
  • Entamoeba hartmanni
  • Entamoeba coli
  • Entamoeba polecki
  • Entamoeba gingivalis
  • Endolimax nana
  • Iodamoeba bütschlii
  • Blastocystis spp.

• • Giardia lamblia (G. duodenalis, G. intestinalis)
  • Dientamoeba fragilis
  • Pentatrichomonas hominis (Trichomonas hominis)
  • Trichomonas tenax
  • Chilomastix mesnili
  • Enteromonas hominis
  • Retortamonas intestinalis
  • Balantidium coli

• Coccidia
  • Cryptosporidium spp.
  • Cyclospora cayetanensis
  • Cystoisospora (Isospora) belli
  • Sarcocystis spp.
• Microsporidia
• Algae (Prototheca)

• • Naegleria fowleri
  • Acanthamoeba spp.
  • Balamuthia mandrillaris
  • Sappinia (diploidea) pedata

• • Trichomonas vaginalis
  • Toxoplasma gondii

• Malaria
• Babesiosis

• Cutaneous Leishmaniasis: General Comments
• Old World (Eastern) Leishmaniasis: Cutaneous Leishmaniasis
• New World (Western) Leishmaniasis: Cutaneous Leishmaniasis
• Visceral Leishmaniasis: General Comments
• Old World (Eastern) Leishmaniasis: Visceral Leishmaniasis
• New World (Western) Leishmaniasis: Visceral Leishmaniasis

• African trypanosomiasis
  • Trypanosoma brucei gambiense
  • Trypanosoma brucei rhodesiense
• American trypanosomiasis
  • Trypanosoma cruzi
  • Trypanosoma rangeli

• Aquatic protist
  • Rhinosporidium seeberi
• Protozoa
  • Lophomonas blattarum
  • Dictyostelium polycephalum
  • Myxozoan parasites
  • Trypanosoma evansi, Trypanosoma lewisi
• Nematodes (the roundworms)
  • Ancylostoma ceylanicum
  • Halicephalobus gingivalis
  • Oesophagostomum spp.
  • Eustrongylides spp.
  • Mermis nigrescens
  • Dioctophyma renale
  • Ternidens deminutus
  • Mammomonogamus laryngeus (Syngamus laryngeus)
  • Ascaris suum
  • Gongylonema pulchrum
  • Haycocknema perplexum
• Cestodes
  • Diplogonoporus spp.
  • Bertiella studeri
  • Inermicapsifer madagascariensis
  • Raillietina celebensis
  • Mesocestoides spp.
  • Taenia crassiceps
• Trematodes
  • Alaria americana
  • Plagiorchis spp.
  • Neodiplostomum seoulense
  • Spelotrema brevicaeca
  • Brachylaima sp.
  • Nanophyetus (Troglotrema) salmincola
  • Stellantchasmus falcatus
  • Phaneropsolus spinicirrus, Phaneropsolus bonnei, and Prosthodendrium molenkempi
  • Haplorchis taichui
  • Gymnophalloides seoi
  • Metorchis conjunctus (North American liver fluke)
  • Schistosoma mattheei
  • Philophthalmus lacrimosus
  • Achillurbainia spp.
• Pentastomids
  • Armillifer spp., Linguatula serrata, and Sebekia spp.
  • Acanthocephalans
  • Macracanthorhynchus hirudinaceus and Moniliformis moniliformis

• • Entamoeba histolytica
  • Free-living amebae
  • Blastocystis spp.
  • Giardia lamblia
  • Toxoplasma gondii
  • Cryptosporidium spp.
  • Cyclospora cayetanensis
  • Cystoisospora (Isospora) belli
  • Sarcocystis spp.
  • Microsporidia
  • Leishmania spp.
  • Strongyloides stercoralis
  • Plasmodium spp.
  • Babesia spp.
  • American trypanosomiasis
  • Crusted scabies

• Health Care-Associated infections
• Gastrointestinal infections
  • Cryptosporidium spp.
  • Giardia lamblia
  • Entamoeba histolytica
  • Microsporidia
  • Cystoisospora (Isospora) belli
  • Hymenolepis nana
  • Taenia solium
• Blood and tissue infections
  • Plasmodium spp.
  • Babesia spp.
  • Trypanosoma brucei gambiense and T. brucei rhodesiense
  • Trypanosoma cruzi
  • Leishmania donovani
  • Toxoplasma gondii
• Infections with ectoparasites
  • Pediculus spp. and Phthirus pubis
  • Sarcoptes scabiei
  • Myiasis
• Infections in the pediatric patient
  • Cryptosporidium spp.
  • Giardia lamblia
  • Pediculus humanus capitis
  • Sarcoptes scabiei
• Infections in the compromised patient
• Laboratory infections
  • Intestinal protozoa
  • Free-living amebae
  • Plasmodium spp.
  • Trypanosoma brucei gambiense and T. brucei rhodesiense
  • Trypanosoma cruzi
  • Leishmania spp.
  • Toxoplasma gondii
  • Specimen handling

• • Amebiasis
  • Giardiasis
  • Toxoplasmosis
  • African trypanosomiasis
  • American trypanosomiasis
  • Malaria
  • Helminth infections

• Protozoal infections
  • Amebiasis
  • Babesiosis
  • Chagas' disease
  • Cryptosporidiosis
  • Cyclosporiasis
  • Giardiasis
  • Leishmaniasis
  • Malaria
  • Toxoplasmosis
  • Trichomoniasis
• Helminth infections
  • Cysticercosis
  • Hydatid disease
  • Fascioliasis
  • Filariasis
  • Onchocerciasis
  • Paragonimiasis
  • Schistosomiasis
  • Strongyloidiasis
  • Toxocariasis
  • Trichinosis
• Intradermal tests
  • Casoni test
  • Montenegro test

• Protozoa
  • Amebae
  • Flagellates
  • Ciliates
  • Coccidia
  • Microsporidia
• Helminths
  • Nematodes
  • Cestodes
  • Trematodes
• Blood Parasites
  • Malaria
  • Leishmania
  • Trypanosomes
  • Filarial Nematodes
• Appendixes

• Arthropods and their relationship to disease
  • Biological vectors of microorganisms
  • Bites and envenomation
  • Tissue invasion
  • Entomophobia and delusional infestation (parasitosis)
• Class Insecta (insects)
  • Order Diptera (flies, mosquitoes, and midges)
  • Myiasis
  • Order Hemiptera (true bugs)
  • Order Coleoptera (beetles)
  • Order Siphonaptera (fleas)
  • Order Anoplura (sucking lice)
  • Order Mallophaga (biting and chewing lice)
  • Order Hymenoptera (bees, wasps, and ants)
  • Order Blattaria (cockroaches)
• Class Arachnida (ticks, mites, spiders, and scorpions)
  • Subclass Acari (ticks, mites, and chiggers)
  • Subclass Araneae (spiders)
  • Subclass Scorpiones (scorpions)
• Other arthropods
  • Class Chilopoda (centipedes)
  • Class Diplopoda (millipedes)
  • Class Crustacea (copepods, crabs, crayfish, etc.)
• Control of arthropods of medical importance
  • Physical control
  • Biological control
  • Chemical control

Chemotherapy plays a very important role not only in reducing patient morbidity and mortality but also in reducing transmission of the parasitic infection. Many of the drugs used to treat parasitic infections have serious side effects; therefore, before initiation of therapy, it is important to consider the following factors: health of the patient, parasite drug resistance, accuracy of the original dose, potential drug toxicity, and the need for follow-up examinations to monitor therapy. The mechanisms of action of most antiparasitic drugs are not well known, including those involving potential drug toxicity to the patient. Because of the limited resources of developing nations, where a majority of parasitic infections occur, there is little commercial incentive for developing effective therapeutics or vaccines. For some drugs, such as triclabendazole, used extensively in veterinary practices, less is known about adverse side effects or toxicity to humans. Specific information can be obtained from the Centers for Disease Control and Prevention, CDC Drug Service, Atlanta, GA (day, 404-639-3670; evenings, weekends, and holidays, 404-639-2888). One can also obtain drugs from CDC that are not commercially available in the United States.

Although common names are frequently used to describe parasitic organisms, these names may represent different parasites in different parts of the world. To eliminate these problems, a binomial system of nomenclature is used in which the scientific name consists of the genus and species. On the basis of life histories and morphology, systems of classification have been developed to indicate the relationships among the various parasite species.

APPENDIX 1 Information Tables

APPENDIX 2 Flowcharts and Staining Tables for Diagnostic Procedures

APPENDIX 3 Common Problems in Parasite Identification

APPENDIX 4 Quality Control Recording Sheets

APPENDIX 5 Commercial Supplies and Suppliers

APPENDIX 6 Reference Sources

APPENDIX 7 “Late-Breaking” Published Information

APPENDIX 8 Molecular Panels for Parasitology

APPENDIX 9 Frequently Asked Questions about Diagnostic Parasitology

APPENDIX 10 Current Procedural Terminology (CPT) Codes in Parasitology