Re: Indonesia Human Cases - April 9, 2008+
Re: Indonesia Human Cases - April 9, 2008+
Thanks Henry, these problems can make it especially difficult to pull out the mild cases of H5N1. Typhus appear to be in the same category of difficulty to make an accurate lab diagnosis. Also a lot of patients therefore just get empiric treatment which now likely includes tamiflu. Would be interesting to know how well tamiflu use is tied to any sort of lab diagnosis of H5N1.
http://www.emedicine.com/MED/topic2332.htm
Typhus
Typhus refers to a group of infectious diseases that are caused by rickettsial organisms and result in an acute febrile illness. Arthropod vectors transmit the etiologic agents to humans. The principle diseases of this group are epidemic or louse-borne typhus and its recrudescent form known as Brill-Zinser disease, murine typhus, and scrub typhus.
Epidemic typhus occurs in Central and South America, Africa, northern China, and certain regions of the Himalayas. Outbreaks may occur when conditions arise that favor the propagation and transmission of lice. Brill-Zinsser disease may occur in approximately 15% of people with a history of primary epidemic typhus.
Murine typhus occurs in most parts of the world, particularly in subtropical and temperate coastal regions. It occurs mainly in sporadic cases, and incidence is probably greatly underestimated in the more endemic regions. Rats, mice, and cats, which are hosts for the disease, are particularly common along coastal port regions. Temperate climates may have a rise in the flea vector and a subsequent rise in the incidence of murine typhus in the summer months. Prior infection with R typhi provides immunity to subsequent reinfection.
Scrub typhus occurs in the western Pacific region, northern Australia, and the Indian subcontinent. Incidence of scrub typhus is largely unknown. Many cases are undiagnosed because of its nonspecific manifestations and the lack of laboratory diagnostic testing in endemic areas. However, a report of incidence of scrub typhus in Malaysia was approximately 3% per month, and multiple infections in the same individual may occur because of a lack of cross-immunity among the various strains of Orientia tsutsugamushi.
Epidemic typhus has the most severe clinical presentation of the typhus group of rickettsial infections. In severe disease, gangrene may occur and lead to loss of digits, limbs, or other appendages. The vasculitic process may also lead to CNS dysfunction, ranging from dullness of mentation to coma, multiorgan system failure, and death. The mortality rate in untreated persons may be as low as 20% in healthy individuals and as high as 60% in elderly or debilitated persons.
Since the advent of widely available antibiotic treatment, mortality rates have fallen to approximately 3-4%. The mortality rate for treated patients with murine typhus is 1-4% and less than 1% for scrub typhus.
Laboratory studies are not particularly helpful in confirming a diagnosis of typhus. These studies assist the clinician in assessing the degree of severity of the illness and in helping exclude other diseases in the differential diagnosis.
http://www.ajtmh.org/cgi/content/abstract/57/1/91
Seroepidemiologic Evidence for Murine and Scrub Typhus in Malang, Indonesia
Indonesian military personnel stationed in Malang, East Java were among troops deployed to central Cambodia as part of the United Nations' Transition Authority Cambodia peace-keeping operation in 1992. Predeployment blood samples obtained from a cohort of Indonesian soldiers indicated a high prevalence of antibodies to antigens of Rickettsia typhi or Orientia (formerly Rickettsia) tsutsugamushi, the etiologic agents for murine and scrub typhus, respectively.