Hematological indicators for neglected tropical diseases
Table 1. Anemia classified based on cell morphology (6, 7)
RBC morphology | Cause | Etiological factors | Typical RBC parameter values |
---|---|---|---|
Normochromic and macrocytic anemias | Nuclear maturation defects: deficient chromatin condensation and extrusion from the cell, with low cell division resulting in large ovalocytes or megaloblasts. | Vitamin B12 deficiency Vitamin B9 deficiency | Low RBC/HCT Normal HGB/MCHC High MCV/MCH/RDW |
Normochromic and normocytic anemias | Hemolytic: increased RBC destruction due to intra- or extra-cellular defects. Hemorrhagic: increased blood loss, acute or chronic. | Hereditary spherocytosis Liver disease Renal diseases Sickle cell disease Hemolytic anemia Acute hemorrhage | Low RBC/HGB/HCT Normal MCV/RDW/MCH/MCHC |
Hypochromic and microcytic anemias | Cytoplasmic maturation defects: deficient hemoglobin synthesis in the cytoplasm | Iron deficiency anemia Thalassemia | Low HGB/MCV/MCH/MCHC Normal RBC/HCT High RDW |
Table 2. Suggested formulas to distinguish beta-thalassemia trait (β-TT) from iron deficiency anemia (IDA) (adopted from Naizi et al. [8] and Jameel et al. [11])
Index | Formula | β-TT | IDA |
---|---|---|---|
Red cell distribution width | RDW | < 14 | < 14 |
RDWI | MCV × RDW / RBC | < 220 | > 220 |
Mentzer | MCV / RBC | < 13 | > 13 |
England & Fraser | MCV – (5 × HGB) - RBC | < 0 (neg) | > 0 (pos) |
Srivastava | MCH / RBC | < 3.8 | > 3.8 |
Shine & Lal | MCV × MCV × MCH / 100 | < 1530 | > 1530 |
Green & King | MCV × MCV × RDW / (HGB × 100) | < 72 | > 72 |
Ricerca | RDW / RBC | < 3.3 | > 3.3 |
Complete blood count in diagnosis of NTDs
Table 3. Hematological implications for neglected tropical diseases caused by infections (1, 13–25)
Disease | Pathogen | Transmission | Manifestation | Hematology implications |
---|---|---|---|---|
Buruli ulcer | Bacteria (Mycobacterium ulcerans) | Not known | Begins with a painless nodule or papule in the skin | Normal |
Chagas disease | Protozoan parasite (Trypanosoma cruzi) | Vector-borne (triatomine bug) Food-borne Congenital (pregnancy, birth Through blood/blood products Organ transplantation Laboratory accidents | Often asymptomatic | Leukocytosis Lymphocytosis Anemia |
Chromoblastomycosis | Fungi (e.g., Fonsecaea pedrosoi, Fonsecaea monophora, Cladophialophora carrionii) | Infected skin injury | Wart-like lesions | Normal |
Dengue | Virus (genus Flavivirus) | Mosquito bites | Hemorrhage | Neutropenia Thrombocytopenia |
Chikungunya | Virus | Mosquito bites | Rash, joint pain | Lymphopenia |
Dracunculiasis | Parasitic worm (Dracunculus medinensis) | Contaminated drinking water | Ulcer | Anemia |
Echinococcosis | Parasitic worms (tapeworms, genus Echinococcus) | Contaminated food | Cysts, often in liver and lungs, containing watery fluid | Eosinophilia Anemia |
Foodborne trematodiases | Parasitic worms (flatworms, e.g., Clonorchis sinensis, Opisthorchis viverrini, O. felineus, Fasciola hepatica, F. gigantica, Paragonimus spp) | Raw fish, aquatic vegetables | Initially, often asymptomatic | Eosinophilia |
Human African trypanosomiasis (HAT) | Protozoan parasite (genus Trypanosoma) | Tsetse fly bites | Local reaction (trypanosomal chancre) | Leukocyte count in cerebrospinal fluid (CSF) Anemia |
Leishmaniasis | Protozoan parasite (genus Leishmania) | Sandfly bites | Ulcer | Lymphocytosis |
Leprosy | Bacteria (Mycobacterium leprae) | Droplets from the nose and mouth | Akin lesions | Lymphocytosis |
Lymphatic filariasis | Parasitic worms (Wuchereria bancrofti, Brugia malayi, Brugia timori) | Mosquito bites | Tissue swelling | Eosinophilia |
Mycetoma | Different species of fungi (eumycetoma) or bacteria (actinomycete) | Infected skin injury | Hard swelling, discharging sinuses and grains | Eumycetoma: Normal Actinomycosis: Leukocytosis Neutrophilia |
Noma | Non-specific polymicrobial organisms | Gum injury | Initial soft tissue lesion (a sore) of the gums | Leukocytosis Neutropenia Anemia |
Onchocerciasis | Parasitic worm (nematode, Onchocerca volvulus) | Black fly bites | Decrease in visual acuity, narrowing of the visual field | Eosinophilia |
Rabies | Virus (genus Lyssavirus) | Zoonotic (e.g., dog bite) | Early symptoms, e.g., itching, pain around site of exposure | Neutrophilia |
Scabies | Parasitic mite (Sarcoptes scabiei hominis) | Skin-to-skin contact | Itching, skin lesions | Eosinophilia |
Schistosomiasis | Parasitic worms (trematodes, e.g., Schistosoma haematobium, Schistosoma mansoni, Schistosoma japonicum) | Skin contact with infested water | Early symptoms, e.g., itching, allergic, gastrointestinal | Eosinophilia Anemia |
Soil-transmitted helminthiases | Parasitic worms, e.g., roundworms (Ascaris lumbricoides), whipworms (Trichuris trichiura), hookworms (Necator americanus and Ancylostoma duodenale) | Contaminated food and drinking water | Diarrhea, abdominal pain | Anemia |
Taeniasis/cysticercosis | Parasitic worm (tapeworm, Taenia solium) | Contaminated food | Often asymptomatic | Eosinophilia |
Trachoma | Bacteria (Chlamydia trachomatis) | Contaminated hands, cloths, and flies | Respiratory infection | Eosinophilia |
Yaws | Bacteria (Treponema pallidum) | From person to person through minor injuries | Hard swelling, ulcer | Anemia Thrombocytopenia Either leukopenia or leukocytosis. Monocytosis is common. |
Enhancing the outreach of diagnostic testing
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References
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