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Arthropod-Borne and Rodent-Borne Virus Infections

Chapter 215 | Harrison's 22e

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[PAGE 1655] Arthropod-Borne and Rodent-Borne Virus Infections 1655 CHAPTER 215 infiltration of the wound(s). With multiple or large wounds, the RIG and Duvenhage virus. Mokola virus, a lyssavirus that has been isolated preparation may need to be diluted in order to obtain a sufficient from shrews with an unknown reservoir species in Africa, may also volume for adequate infiltration of all wound sites. If the exposure produce human disease indistinguishable from rabies. involves a mucous membrane, the entire dose should be administered IM. Rabies vaccine and RIG should never be administered at the I VESICULAR STOMATITIS VIRUS same site or with the same syringe. Commercially available RIG in the Vesicular stomatitis is a viral disease of cattle, horses, pigs, and some United States is purified from the serum of hyperimmunized human wild mammals. Vesicular stomatitis virus is a member of the genus donors. These human RIG preparations are much better tolerated than Vesiculovirus in the family Rhabdoviridae. Outbreaks of vesicular stoma- are the equine-derived preparations still in use in some countries (see titis in horses and cattle occur sporadically in the southwestern United below). Serious adverse effects of human RIG are uncommon. Local States. The animal infection is associated with severe vesiculation and pain and low-grade fever may occur. ulceration of oral tissues, teats, and feet and may be clinically indistin- Two purified inactivated rabies vaccines are available for rabies PEP guishable from the more dangerous foot-and-mouth disease. Epidemics in the United States. They are highly immunogenic and remarkably are usually seasonal, typically beginning in the late spring, and are prob- safe compared with earlier vaccines. Four 1-mL doses of rabies vaccine ably due to arthropod vectors. Direct animal-to-animal spread can also should be given IM in the deltoid area. (The anterolateral aspect of the occur, although the virus cannot penetrate intact skin. Transmission thigh also is acceptable in children.) Gluteal injections, which may not to humans usually results from direct contact with infected animals always reach muscle, should not be given and have been associated (particularly cattle) and occasionally follows laboratory exposure. In with rare vaccine failures. Ideally, the first dose should be given as human disease, early conjunctivitis is followed by an acute influenza-like soon as possible after exposure; failing that, it should be given without illness with fever, chills, nausea, vomiting, headache, retrobulbar pain, further delay. The three additional doses should be given on days 3, myalgias, substernal pain, malaise, pharyngitis, and lymphadenitis. Small 7, and 14; a fifth dose on day 28 is no longer recommended except in vesicular lesions may be present on the buccal mucosa or on the fingers. immunocompromised patients. Pregnancy is not a contraindication for Encephalitis is very rare. The illness usually lasts 3–6 days, with complete immunization. Glucocorticoids and other immunosuppressive medi- recovery. Subclinical infections are common. A serologic diagnosis can cations may interfere with the development of active immunity and be made on the basis of a rise in titer of complement-fixing or neutral- should not be administered during PEP unless they are essential. Rou- izing antibodies. Therapy is symptom-based. tine measurement of serum neutralizing antibody titers is not required, FURTHER READING but titers should be measured 2–4 weeks after immunization in immu- Fooks AR et al: Current status of rabies and prospects for elimination. nocompromised persons. Local reactions (pain, erythema, edema, and Lancet 384:1389, 2014. pruritus) and mild systemic reactions (fever, myalgias, headache, and Fooks AR, Jackson AC (eds): Rabies: Scientific Basis of the Disease nausea) are common; anti-inflammatory and antipyretic medications and Its Management, 4th ed. London, Elsevier Academic Press, 2020. may be used, but immunization should not be discontinued. Systemic Jackson AC: Treatment of rabies. In: Post TW, ed. UpToDate. allergic reactions are uncommon, but anaphylaxis does occur rarely Waltham, Massachusetts: Wolters Kluwer, 2023. www.uptodate.com. and can be treated with epinephrine and antihistamines. The risk of Letchworth GJ et al: Vesicular stomatitis. Vet J 157:239, 1999. rabies development should be carefully considered before the decision Manning SE et al: Human rabies prevention—United States, 2008: is made to discontinue vaccination because of an adverse reaction. Recommendations of the Advisory Committee on Immunization Most of the burden of rabies PEP is borne by persons with the fewest Practices. MMWR Recomm Rep 57:1, 2008. resources. In addition to the rabies vaccines discussed above, vaccines World Health Organization: WHO Expert Consultation on Rabies: grown in either primary cell lines (hamster or dog kidney) or con- Third Report (WHO Technical Report Series No. 1012). Geneva, tinuous cell lines (Vero cells) are satisfactory and are available in many World Health Organization, 2018. Available at https://iris.who.int/ countries outside the United States. Less expensive vaccines derived bitstream/handle/10665/272364/9789241210218-eng.pdf. Accessed from neural tissues are still used in a diminishing number of develop- September 20, 2024. ing countries; however, these vaccines are associated with serious neu- roparalytic complications, including postinfectious encephalomyelitis and Guillain-Barré syndrome. The use of these vaccines should be discontinued as soon as possible, and progress has been made in this regard. Worldwide, more than 10 million individuals receive postexpo- sure rabies vaccine each year. If human RIG is unavailable, purified equine RIG can be used in the same manner at a dose of 40 IU/kg. The incidence of anaphylactic reac- 215 Arthropod-Borne and tions and serum sickness has been low with recent equine RIG products. Rodent-Borne Virus Preexposure Rabies Vaccination Preexposure rabies prophy- laxis should be considered for people with an occupational or rec- Infections reational risk of rabies exposures and also for certain travelers to rabies-endemic areas. The primary schedule consists of two doses of Jens H. Kuhn, Ian Crozier rabies vaccine given on days 0 and 7. Serum neutralizing antibody tests help determine the need for subsequent booster doses. When a previ- ously immunized individual is exposed to rabies, two booster doses of This chapter summarizes the major features of selected arthropod- vaccine should be administered on days 0 and 3. Wound care remains borne and rodent-borne viruses and associated infections and/or essential. As stated above, RIG should not be administered to previ- disease. Numerous viruses of this category are spread in nature among ously vaccinated persons. animals without ever infecting humans. Other viruses incidentally OTHER RHABDOVIRUSES infect humans, with few causing disease. Some viruses are regularly introduced into the human population by arthropods (specifically, OTHER LYSSAVIRUSES insects and ticks) or by chronically infected rodents. A growing number of lyssaviruses other than rabies virus have been These zoonotic viruses are taxonomically diverse and therefore dif- discovered to infect bat populations in Europe, Africa, Asia, and fer fundamentally in virion morphology, replication strategy, genomic Australia. Six of these viruses have produced a very small number organization, and genome sequence. Although a virus’s classification of cases of a human disease indistinguishable from rabies, including in a taxon is enlightening regarding natural maintenance strategies, European bat lyssaviruses 1 and 2, Australian bat lyssavirus, Irkut virus, sensitivity to antiviral agents, and aspects of pathogenesis, it does not [PAGE 1656] 1656 PART Infectious Diseases necessarily predict which clinical symptoms and signs (if any) the (S, ≈ 1–2 kb; medium [M], 3.6