Acute Clinical Course |
Malaria | Plasmodium falciparum, P. malariae, P. vivax P. ovale | Asia, Africa, South and Central America As above; limited in Africa; foci in Asia | Vector (mosquito) | 7–339 days; rare reports of P. falciparum 2 years and P. vivax 5 years after exposure | Fever (possibly cyclical, every 48 or 72 h), rigors, headache, night sweats, weakness, altered mental status | Serial Giemsa-stained blood smears demonstrating intraerythrocytic parasites; rapid antigen capture assay | Chloroquine (if acquired in chloroquine-sensitive area); mefloquine or atovaquone + proguanil or quinine + doxycycline; primaquine for P. vivax | Bed nets, insect repellents, vector control, chemoprophylaxis | 123 |
Hepatitis A | Hepatitis A virus (HAV) | Worldwide: highest prevalence in developing world | Fecal-oral | 15–50 days | Fever, malaise, anorexia, nausea, abdominal pain, jaundice, elevated aminotransferases | Serology: anti-HAV IgM | Supportive; no specific treatment | Food and water hygiene; passive immunization with pooled immunoglobulin; active immunization with killed vaccine | 99 |
Hepatitis B | Hepatitis B virus (HBV) | Worldwide; highest prevalence in developing world | Percutaneous or sexual exposure to infected body fluids | 45–180 days | Malaise ± fever, anorexia, nausea, vomiting, abdominal pain, jaundice, elevated aminotransferases | Serology: HBV surface antigen positive, IgM anti-HBV core antibody | Supportive; no specific therapy for acute disease | Personal protective measures; screening of blood supply; use of sterile needles; immunization with recombinant vaccine | 99 |
Hepatitis E | Hepatitis E virus (HEV) | Asia, north and west Africa, Mexico | Fecal-oral | 15–64 days | Fever, malaise, anorexia, nausea, abdominal pain, jaundice, elevated aminotransferases | Serology: anti-HEV IgM | Supportive; no specific therapy for acute disease | Food and water hygiene | 99 |
Rabies | Rhabdovirus (member of genus Lyssavirus) | Worldwide: in developing world, domestic and feral animals; in developed world, wild animals | Exposure to saliva of infected animals; rarely, airborne transmission in bat roosting caves | 9 days to >1 year (rare) | Heralded by headache, fever, apprehension, paresthesias near site of exposure; progression to paresis, muscle spasm, dysphagia, hydrophobia, delirium, seizures | Direct fluorescent antibody staining of brain tissue (animal or human) or skin on back of neck; RT-PCR on CSF, saliva, tissue | Supportive; no specific therapy for acute disease | Before exposure: active vaccination. After exposure: treatment to prevent active disease (wound care; passive immunization with human rabies immune globulin infiltrated into site of exposure; active immunization with vaccine) | 105 |
Leptospirosis | Leptospira interrogans serovars | Worldwide | Contact of skin or mucous membranes with freshwater or soil contaminated with urine of infected animals | 10–21 days | Fever, headache, myalgia, conjunctival suffusion, possibly in association with jaundice, meningitis, mental status changes, hemolysis, hepatitis, myocarditis, and pneumonia. Illness may be biphasic and become chronic. | Serology: IgM antibodies; organism isolation in culture from blood, urine, or CSF during acute phase of illness | Oral doxycycline for mild disease; parenteral ceftriaxone or penicillin for severe disease | Personal protective measures when exposure cannot be avoided; doxycycline prophylaxis in high-risk exposures | 80 |
Scrub typhus | Orientia tsutsugamushi | Central, southeastern, and eastern Asia | Vector (chiggers [mite larvae]) | 6–21 days | Fever, headache, myalgia, arthralgia, conjunctival injection, malaise, cough, transient maculopapular rash, eschar at site of mite attachment | Serology: Weil-Felix test detects cross-reacting antibodies to Proteus mirabilis OX-K. | Doxycycline or chloramphenicol | Personal protective measures; doxycycline prophylaxis | 83 |
Chronic or Relapsing Clinical Course |
Cutaneous leishmaniasis | Old World: Leishmania major, L. tropica, L. infantum-donovani New World: L. mexicana complex, L. braziliensis complex | Southwest and central Asia, China, Africa, Central and South America | Vector (Phlebotomus spp. sandfly) | 2–8 weeks (up to 18 months) | Single or multiple chronic, painless, nodular or ulcerative skin lesions ± eschar near inoculation sites on head and limbs, associated with spontaneous healing and scarring after 5–12 months; rare chronic or relapsing forms | Parasites in Wright-Giemsa-stained skin scraping, slit skin smear, or biopsy specimen; culture or PCR for speciation | Vigilant monitoring for spontaneous resolution; pentavalent antimony; oral azoles | Personal protective measures (sandflies can penetrate mosquito nets; permethrin coating enhances efficacy); vector and animal reservoir control | 126 |
Visceral leishmaniasis (kala-azar) | L. infantum-donovani | Southwest and central Asia, Brazil, India, China, Africa | Vector (Phlebotomus spp. sandfly) | 2–14 months (rarely up to 2 years) | Chronic fever, cachexia, anorexia, weight loss, pancytopenia, hepatosplenomegaly | Parasites in tissue (bone marrow, liver, lymph node, spleen) on histopathologic staining, culture, or PCR; rK39 serologic assay | Liposomal amphotericin B, pentavalent antimony, miltefosine | Personal protective measures, vector and animal reservoir control | 126 |
Tuberculosis | Mycobacterium tuberculosis | Worldwide | Inhalation of aerosols from individuals with active pulmonary tuberculosis | 1 month to many years | Fever, weight loss, night sweats, cachexia, cough, hemoptysis, pulmonary infiltrates | Sputum acid-fast smears, mycobacterial culture, nucleic acid amplification | Multidrug therapy (number depends on risk of drug resistance) including combination of isoniazid, rifampin, pyrazinamide, ethambutol, and others | Personal protective measures; chemoprophylaxis for skin test conversion | 74 |
Q fever | Coxiella burnetii | Worldwide | Inhalation of aerosols from infected secretions of livestock herd or parturient animal; ingestion of raw milk | 2–5 weeks for acute disease; chronic manifestations may present indolently over many years | Acute: undifferentiated febrile illness, atypical pneumonia Chronic: granulomatous hepatitis, culture-negative endocarditis, osteomyelitis (including vertebral), fever of unknown origin | Serology: complement-fixation antibody titer to phase I antigen | Doxycycline (with hydroxychloroquine for endocarditis) | Avoidance of unpasteurized products | 83 |
Brucellosis | Brucella abortus, B. melitensis, B. suis | Worldwide; especially prevalent in southwest and central Asia, India | Inhalation of infected animal materials, ingestion of raw milk, direct animal contact | 5 days to months | Skeletal, genitourinary, or pulmonary disease; chronic meningitis | Organism isolation from blood, bone marrow; Brucella-specific antibody | Doxycycline + rifampin or streptomycin | Personal protective measures, avoidance of unpasteurized dairy products | 66 |
Melioidosis | Burkholderia pseudomallei | Southeast Asia | Percutaneous inoculation from environmental sources; respiratory route, including possible inhalation in dusts raised by helicopter blades during military operations | 1–21 days; may become clinically apparent or relapse years after exposure | Chronic, suppurative skin and soft tissue infections; osteomyelitis; chronic cavitary pneumonia; septicemia | Isolation of organism in culture | Ceftazidime or carbapenem; possible use of trimethoprim-sulfamethoxazole as eradication therapy | Personal protective measures and wound hygiene | 61 |
Echinococcal (hydatid) disease | Echinococcus granulosus; E. multilocularis | Worldwide (E. granulosus); north Asia (E. multilocularis) | Ingestion of eggs from feces-contaminated soil | Months to years | Symptoms related to progressive enlargement of cystic lesions in liver, lungs, brain, bone | Immunologic assay (ELISA) in setting of consistent imaging picture | Albendazole therapy followed by surgical excision (with or without instillation of cysticidal agent) | Animal hygiene and control measures | 135 |
Schistosomiasis | Schistosoma haematobium (urinary tract); S. mansoni, S. japonicum (biliary tract); S. mekongi | S. mansoni: Africa, southwest Asia, South America; S. japonicum: Far East; S. mekongi: southeast Asia; S. haematobium: Africa, southwest Asia | Freshwater via exposure to snail intermediate hosts | 14–84 days for acute manifestations (Katayama fever); chronic manifestations over years | Katayama fever: fever, headache, malaise, dry cough, dyspnea, transient urticarial rash Chronic: Terminal hematuria, dysuria, frequency (S. haematobium); abdominal pain, eosinophilia, hepatosplenomegaly, sequelae of portal hypertension (S. mansoni,S. japonicum) | Urine or fecal examination for eggs; bladder biopsy; serology for antibodies to schistosomes | Praziquantel | Personal protective measures in freshwater; snail control via molluscicides | 134 |
Histoplasmosis | Histoplasma capsulatum | Africa, Americas, Far East | Inhalation of airborne environmental conidia | 3–17 days for acute manifestations; chronic manifestations over months to years | Chronic, systemic disease with fever, weight loss, fatigue, cytopenias, hepatosplenomegaly; chronic pulmonary disease similar to tuberculosis | Fungal visualization in stained tissue specimens; serum or urine antigen detection | Itraconazole or ketoconazole | Personal protective measures in selected high-risk environments, such as caves, pigeon roosts, chicken houses | 111 |
Extrain-testinal amebiasis | Entamoeba histolytica | Worldwide | Fecal-oral | 11–21 days | Fever, abdominal pain, watery diarrhea; right-upper-quadrant tenderness, hepatomegaly | Stool antigen assay; serum amebic antibodies in liver abscess | Metronidazole + paromomycin or diloxanide furoate; dehydroemetine + paromomycin or diloxanide furoate | Food and water hygiene | 122 |
Giardiasis | Giardia lamblia | Worldwide | Fecal-oral | 7–10 days | Chronic diarrhea, abdominal pain, bloating, nausea, flatus due to postinfectious irritable bowel syndrome or protein-losing enteropathy; postinfection fatigue | Fecal, string test, or duodenal aspirate microscopy; stool antigen assay | Metronidazole for ongoing infection; no specific antiparasitic therapy for postinfectious syndromes | Food and water hygiene | 129 |
Cryptosporidiosis | Cryptosporidium spp. | Worldwide | Fecal-oral | 3–6 days | Symptoms as above; chronic watery diarrhea, with or without fever, abdominal pain, nausea in immunocompromised hosts | Fecal microscopy or intestinal biopsy; stool antigen assay | No specific antiparasitic therapy for postinfectious syndromes | Food and water hygiene | 129 |
Strongyloidiasis | Strongyloides stercoralis | Tropical and subtropical climates | Fecal-oral as initial route; persistent infection can result from autoinfection in human host | 11–28 days | Abdominal pain, persistent diarrhea, urticaria; disseminated disease can cause wasting, pulmonary symptoms, eosinophilia (predilection for immunocompromised hosts) | Stool antigen detection assay; serology | Ivermectin; thiabendazole or albendazole as second-line alternatives | Personal protective measures, including wearing shoes in endemic areas (infective larvae penetrate intact skin) | 132 |
Sandfly fever (convalescence) | Phleboviruses | Africa, Asia, South and Central America | Vector (Phlebotomus spp. sandfly) | Weeks to months for convalescent symptoms | Depression, fatigue, generalized weakness | Serology | No specific therapy | Personal protective measures; vector control | 106 |
Relapsing fever | Borrelia recurrentis (louse-borne, epidemic), Borrelia spp. (tick-borne, endemic) | Worldwide | Vector (body louse; soft tick) | 4–18 days initially, with relapses after 7- to 10-day intervals | Recurrent episodes of fever, rigors, diaphoresis, headache, myalgias, arthralgias, asthenia lasting 3–6 days and alternating with symptom-free periods | Spirochetes on stained peripheral-blood smear during febrile episodes | Tetracycline or erythromycin; antibiotic treatment may lead to Jarisch-Herxheimer reaction with fever, rigor, hypotension within 2 h of initiation | Personal protective measures; vector control | 81 |
Brill-Zinsser disease | Rickettsia prowazekii | Worldwide | Vector (body louse) | Recrudescent disease years after primary episode of epidemic typhus | Mild febrile illness with systemic symptoms and macular eruption | Serology | Doxycycline or chloramphenicol | Vector control; personal protective measures; appropriate treatment of initial typhus episode | 83 |
Chronic wound infection | Acinetobacter spp., other gram-negative organisms; Staphylococcus aureus, including MRSA; invasive molds (Aspergillus, Fusarium, Mucor, Absidia spp.); atypical mycobacteria (M. chelonei, M. abscessus) associated with draining sinuses | Worldwide | Inoculation via combat wounds and penetrating injury | Weeks to months; progression of acute infection | Chronic pain, swelling, ± serosanguineous or purulent drainage of infected site with or without constitutional symptoms/signs | Culture of tissue | Guided by results of cultures and in vitro antibiotic susceptibility testing; carbapenem ± amikacin as empirical therapy for multidrug-resistant Acinetobacter; colistin if resistant | Adequate initial wound debridement and treatment of acute soft-tissue infection; removal of foreign bodies; strict adherence to infection control precautions to prevent nosocomial infection | Miscellaneous |
Chronic osteomyelitis | Acinetobacter baumannii and other gram-negative pathogens; S. aureus, including MRSA | Worldwide | Foreign bodies (projectiles); contiguous spread from soft tissue infection | Weeks to months | Chronic pain, swelling of infected site with or without constitutional symptoms/signs | Culture of bone biopsy | Treatment as above | Adequate initial wound debridement and treatment of soft tissue infection; removal of foreign bodies; strict adherence to infection control precautions to prevent nosocomial infection | 28 |
Leprosy | Mycobacterium leprae | Southeast and south Asia, tropical Africa, Brazil | Skin, mucous membrane, or fomite contact | 4–10 years | Skin lesions, cutaneous hypoesthesia, peripheral-nerve enlargement | Acid-fast bacilli in skin biopsy | Dapsone + rifampin ± clofazimine | Multidrug therapy to prevent chronic sequelae | 75 |
Filariasis | Wuchereria bancrofti, Brugia malayi, Brugia timori | Wuchereria: tropical and subtropical areas of Africa, Asia, Americas; Brugia: southeast and south Asia | Vector (mosquito) | 5–18 months | Pain and swelling of arms, legs, genitalia; headache, nausea, fatigue, eosinophilia | Identification of microfilariae on nocturnal, Giemsa-stained peripheral-blood smear | Diethylcarbamazine or ivermectin to possibly reduce microfilarial counts in blood; no proven effective drug therapy for lymphatic disease | Vector control, personal protective measures | 133 |
Visceral larva migrans | Toxocara canis, T. catis | Worldwide | Ingestion of eggs from feces-contaminated soil | Weeks to months | Eosinophilia, rash, fever, pneumonitis, chronic abdominal pain | Serology | No proven effective therapy; usually self-limited | Food and personal hygiene | 131 |
Hepatitis C | Hepatitis C virus (HCV) | Worldwide | Bloodborne, less efficient sexual transmission | Years | Chronic hepatitis leading to cirrhosis in minority | Serology: HCV antibody | Combination antiviral therapy | Bloodborne precautions; condom use | 100 |
HIV-1 infection | Human immunodeficiency virus type 1 | Worldwide | Bloodborne, sexual | Years | Constitutional symptoms and signs, opportunistic infections | Serology, viral PCR | Combination highly active antiretroviral therapy | Bloodborne precautions; condom use | 97 |
HTLV-I infection | Human T cell lymphotropic virus type I | Foci of infection in Central and South America, sub-Saharan Africa | Bloodborne, sexual | Years | T cell leukemia/lymphoma, chronic progressive myelopathy/tropical spastic paraparesis | Serology, viral PCR | No specific antiviral therapy | Bloodborne precautions; condom use | ... |