These considerations are also relevant to places like PNG and Nepal, especially given the relative lack of lab diagnostics. Please share your questions or comments about other causes that are relevant in your localities!
There is a long list that will vary according to your locale. Across Northern NSW, the important ones to consider include:
- Viral illnesses including influenza, adenovirus, viral hepatitis, parvovirus, EBV and CMV
- Rickettsial disease (spotted fevers, rarely murine typhus). See useful information page from NSW Health.
- Q Fever (Coxiella burnetti) (low platelets often, moderately abnormal liver function tests)
- Brucellosis (wild pig hunters !)
- Leptospirosis
In certain overseas travelers, the most important considerations include:
- malaria (evidence of haemolysis, low Hb, low platelets also often seen- at least 3 negative smears/ICTs required to exclude)
- typhoid fever (abnormal liver function, high CRP, positive blood and/or stool cultures)
- dengue and other arboviral diseases (low platelets, neutropenia as well, CRP relatively normal)
- scrub typhus (Orientia tsutsugumushi)
- measles
Microbiology and Infectious Diseases postgraduate teaching (PRIDA) 