Non-specific
| Parasitic | Malaria (Plasmodium spp) |
P falciparum
| 7 days to 1 year | Worldwide tropics | Risk highest in West Africa. Spread by female mosquitoes | History of mosquito bites is unreliable. Painless and non-irritant. Only P falciparum causes neurological illness |
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P vivax
| 14 days–2 years | Worldwide tropics | | |
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P ovale
| 14 days–2 years | Mainly Africa | | |
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P malariae
| 14 days–?years | Africa | | |
| Bacterial | Typhoid | | 3–56 days (average 10–20) | Worldwide | Poor sanitation | Imported cases usually from South Asia |
| Viral | HIV | | 7–28 days | Worldwide | Sexual contact, injecting drug use | 95% patients seropositive at 6 months |
Encephalitis
| Viral | Enteroviruses | | 3–8 days | Worldwide | Recent epidemics Taiwan | |
| | Herpes viruses | HSV | Highly variable | Worldwide | | Can also cause meningitis |
| | | Varicella zoster | 13–21 days | Worldwide | | Usually a cerebellar encephalitis |
| | | B virus | 2–10 days | | Macaque bites | Prophylactic acyclovir recommended |
| | Arboviruses | JEV | 5–15 days | SE Asia | Seasonal peaks in transmission | Mosquito borne |
| | | WEE | 5–15 days | Western USA, South America | | |
| | | EEE | 5–15 days | Eastern USA | | |
| | | VEE | 2–6 days | South America | | |
| | | SLE | 5–15 days | USA | | |
| | | WNV | 3–12 days | America, North Africa, SE Asia, ?UK/Europe | | |
| | | MVE | 5–15 days | South Australia | | |
| | | TBE | 7–14 days | Central, Northern Europe, Asia | | Tick borne |
| | Rabies | | 3 days–many years | Rare in developed countries | Animal bites/scratches | Incubation period <90 days in 85% cases |
| Bacterial | Louse borne typhus | | 7–14 days | Worldwide | Disease of poverty and destitution; rare in tourists, aid workers possibly at risk | Human louse |
| | Rocky mountain spotted fever | | 2–14 days | USA, Canada, Mexico, South America | Can occur in urban environments | Tick borne |
| | Brucellosis | | 5–60 days | Middle East, South America, Northern Ireland | Unpasteurised dairy produce, contact with farm animals | Meningitis and encephalitis can arise as a result of brucellosis. CSF shows predominant lymphocytosis, raised protein, and normal glucose |
| | Secondary syphilis | | 6–14 weeks | | Sexual contact | Prominent and distinctive rash |
| Parasitic | African trypanosomiasis | | T b gambiense: months/years. T b rhodesiense: weeks | Disease occurs in Africa in isolated pockets | Travel to rural areas e.g. Safari | Spread by tsetse flies. Seek expert help. If suspected may be necessary to start treatment before lumbar puncture |
Meningitis
| Viral | EV71, echo, coxsackie | | 3–8 days | Worldwide | | |
| | Polio | | 7–14 days | Eradicated from the Americas | | Almost(!) eradicated |
| | Mumps | | 12–25 days | Worldwide | Adults | Meningitis can occur in the absence of parotitis |
| | EBV | | 35–45 days | Worldwide | Young adults | |
| | CMV | | 3–8 weeks | Worldwide | | |
| | LCV | | 6–13 days | | Animal handlers, the poor | Infection from rodent droppings |
| | HIV | | 7–28 days | | | |
| Bacterial | Meningococcus | | Hours–days | Worldwide, but especially Sub-Saharan Africa, Middle East | Haj pilgrims | Outbreaks common in pilgrims returning to UK |
| | Pneumococcus | | | Worldwide | Note: penicillin resistance common in some countries (e.g. Spain, South Africa) | |
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Haemophilus influenzae
| | | | | |
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Streptococcus suis
| | | China, VietNam | Contact with pigs | |
| | Listeriosis | | | | Unpasteurised dairy products | |
| | Leptospirosis | | 2–26 days | | Watersports | |
| | Brucellosis | | As before | | | |
| | Lyme disease (stage 2) | | Weeks to months | North America, Europe | Hiking/camping | 15% of patients affected |
| | Syphilis | | As before | | | |
| | Tuberculosis (TB) | | Usually represents reactivation of latent disease | | Insidious onset | Good outcome depends upon prompt diagnosis and treatment |
| Fungal | Cryptococcosis | | Weeks | Depends upon variety | Not clearly defined | Disease can occur in the immunocompetent in the tropics |
| | Blastomycosis | | Not determined | USA, Canada, Africa, India, Middle East | Possibly associated with river banks | Usually evidence of skin or respiratory involvement |
| | Histoplasmosis | | Days to weeks | Worldwide excluding Europe | Associated with bat and bird droppings | Different disease syndromes depending on region |
| | Coccidiomycosis | | 10–30 days | Semi-desert areas of the New World | Initial flu-like symptoms | Associated with erythema nodosum. CSF findings similar to TB(M) |
| Parasitic—causes of eosinophilic meningitis | Schistosomiasis | | Weeks to months, sometimes years | Africa, South America, SE Asia, China | Tropical fresh water contact | Extremely common in sub-Saharan Africa |
| | Gnathostomiasis | | | SE Asia, Pacific Basin | Gastronomes | Raw and pickled fish, shellfish, amphibian ingestion |
| | Angiostrongyliasis | | | | | |
| | Sparganosis | | | Widespread in Americas and tropics | | Frog and snake ingestion |
| | Cysticercosis (Taenia solium, pork tapeworm) | | | Central, South America, Asia, Africa | Swine/measley pork | All but eradicated from industrialised countries |
| | Strongyloidiasis | | | Worldwide | Poor sanitation | As part of hypereosinophilic syndrome |
Fits
| Bacterial | Tetanus | | 3–21 days | Worldwide | Tetanic spasms may mimic seizures | |
| | TB meningitis | | As for TB(M) | | | |
| | Cerebral abscess | | Onset usually 1–4 weeks | | | |
| Parasitic | Cysticercosis | | See above | As before | | Most common cause of fits worldwide |
| | Schistosomiasis | | See above | As before | | |
| | Hydatid disease | | | Worldwide | Communities with close exposure to dogs | Especially Middle East |
| | Amoebic brain abscess | | Weeks to months | Worldwide | Poor sanitation | Can be single or multiple |
| Drugs | Mefloquine, chloroquine ciprofloxacin | | Chloroquine, mefloquine, and ciprofloxacin are contraindicated in patients with epilepsy | | | |
Paralysis
| Viral | Rabies | | As above | As before | May be more common after contact with bats | “Paralytic” or “dumb” rabies |
| | Polio | | 7–14 days | See above | | |
| | Japanese encephalitis | | 5–15 days | | | Produces a syndrome similar to polio in 5% of cases |
| | Enteroviruses | | | | Coxsackie, echoviruses, EV70, EV71 | |
| Bacterial | Tetanus | | 3–21 days | Worldwide | History of injury in only 50% | |
| | Botulism | | 12–72 hours | Rare in developed world | Usually food borne but can result from wound infection | |
| Post-infectious | Guillain-Barré syndrome | | | | | Associated with campylobacter, EBV, echovirus, VZV, HIV, and infection |
| Ectoparasites | Tick bites | | 5–6 days | All continents | Hikers/campers, etc | Usually resolves rapidly with tick removal |
| Algae | Paralytic shellfish poisoning, ciguateratoxin poisoning | | 30 mins to 6 hours | Latitudes 30°–35° N to 30°–30° S | Seafood lovers | Dinoflagellate toxins concentrated through food chain |