Fleas (order Siphonaptera)
Eric S. Loker, Bruce V. Hofkin in Parasitology, 2015
Hosts and transmission Although they often have preferred hosts, most fleas are not highly host specific, readily transferring between hosts of different species. For instance, the cat flea C. felis readily uses both cats and dogs, as well as humans and other mammals as hosts. Various flea species transmit a variety of viral, bacterial, and eukaryotic parasites. The most important flea-borne disease is bubonic plague, caused by the bacterium Yersinia pestis. The most important vector species is probably the oriental rat flea Xenopsylla cheopis, but other species, including Pulex irritans, the human flea, are capable of transmitting plague. Rickettsia typhi, the bacterium responsible for murine typhus, is transmitted by several flea species. Myxoma virus, a pathogen in rabbits, is transmitted by several arthropods including fleas. C. felis, C. canis, and P. irritans all serve as intermediate hosts of the tapeworm Dipylidium caninum (see page 459). Trypanosomes in the subgenus Herpetosoma, and tapeworms in the genus Hymenolepis may also be vectored by fleas.
Fleas
Jerome Goddard in Public Health Entomology, 2022
Murine typhus. The rickettsial disease called murine typhus is transmitted to humans by fleas and is characterized by headache, chills, prostration, fever, and general pains. There may be a macular rash, especially on the trunk. Infection occurs when infectious flea feces are rubbed into the fleabite wound or other breaks in the skin. Murine typhus is usually mild with negligible mortality, except in the elderly, although severe cases occasionally occur with hepatic and renal dysfunction. For many years, there were only about 100 cases of murine typhus reported annually in the United States.8,9 However, a recent paper reported 90 cases of murine typhus from just 2 Texas hospitals over a 3-year period.10 The classic cycle involves rat-to-rat transmission with the oriental rat flea, Xenopsylla cheopis, being the main vector; however, the classic cycle seems to have been replaced in suburban areas by a peridomestic animal cycle involving free-ranging cats, dogs, opossums, and their fleas.11 Murine typhus is one of the most widely distributed arthropod-borne infections endemic in many coastal areas and ports throughout the world.11
The Pathogenesis and Pathology of the Hemorrhagic State in Viral and Rickettsial Infections
James H. S. Gear in CRC Handbook of Viral and Rickettsial Hemorrhagic Fevers, 2019
At the onset, murine typhus is manifested by headache, myalgia, fever, chills, nausea, vomiting, abdominal pain, and weakness. A blanchable, macular rash appears on the abdomen, shoulders, chest, arms, and thighs, usually on the 5th day of illness with a range of 2 to 8 days. The rash later becomes maculopapular and occasionally petechial. Other clinical features may include cough, hemoptysis, tachycardia, basilar rales, hypotension, conjunctival hyperemia, and diarrhea or constipation. Fatality is rare, being observed once in Maxcy’s series of 114 cases133a and in none of Stuart and Pullen’s series of 180 cases.134 Hemorrhagic diathesis is quite rare.
Murine typhus
Published in Baylor University Medical Center Proceedings, 2022
Seamus Lonergan, Gowtham Ganesan, Stephen J. Titus, Kashif Waqiee Ahmed
Murine typhus is caused by flea-to-human transmission of the gram-negative bacterium R. typhi. Symptoms of illness include fever, headache, myalgias, abdominal pain, nausea, vomiting, or diarrhea. Rarely, hepatosplenomegaly and cardiomegaly have been reported.3–6 In the US, the number of cases has risen from 495 in 2000 to 5500 in 2018. The illness is most common in May through August.7 Cases are mostly mild, with a 1% to 4% fatality rate without treatment.8
Antinuclear antibodies in infectious diseases
Published in Infectious Diseases, 2020
Jae Hyoung Im, Moon-Hyun Chung, Young Kyoung Park, Hea Yoon Kwon, Ji Hyeon Baek, Seung Yun Lee, Jin-Soo Lee
IFA tests to detect antibodies against O. tsutsugamushi, B. henselae, SFG, and murine typhus were conducted using in-house assays. Results of >1:40 were defined as seropositive. IFA tests to detect antibodies against O. tsutsugamushi, B. henselae, SFG of Rickettsia, and R. typhus were performed as previously described [12–15].
Related Knowledge Centers
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