Continuing medical educationEctoparasites: Pediculosis and tungiasis
Section snippets
Key points
- •
Body lice infestation is associated with poor hygiene or neglect
- •
Given a homelessness epidemic, the diagnosis and management of body lice are essential dermatology skills
- •
Body lice are vectors for potentially life-threatening pathogens
Lice are obligate parasites, feeding exclusively on the blood of infested hosts.1 Among thousands of lice species, only Pediculus humanus (P humanus) and Phthirus pubis (pubic lice) require humans as hosts. P humanus includes 2 morphotypes: P humanus corporis (body)
Key points
- •
Head lice are a public health problem affecting all demographics
- •
Head lice can be infected with pathogens
- •
Novel US Food and Drug Administration (FDA)–approved topical therapies include benzyl alcohol 5% lotion, spinosad 0.9% suspension, and ivermectin 0.5% lotion
Head lice are ovoid-shaped, 2- to 3-mm arthropods (Fig 3, A).59, 60 Head lice are obligate human parasites that spend their entire life cycle on the scalp, feeding off blood every few hours.61 Female lice live ≤30 days and lay
Key points
- •
Pubic lice infestation can involve multiple body regions
- •
A diagnosis warrants screening for other sexually transmitted infections and, in children, considering the possibility of abuse
Pubic lice measure 0.8 to 1.2 mm in diameter and are wider than they are long, unlike ovoid-shaped head and body lice.60 This crab-like shape enables them to grasp widely spaced pubic hairs (Fig 4, A). Female lice lay roughly 30 eggs during their 3- to 4-week lifespan.111
Epidemiology
Pubic lice are transmitted via close
Key points
- •
Tungiasis is an infestation, endemic to tropical world regions, caused by a flea burrowing into the skin
- •
Tungiasis is seen in travelers returning from endemic areas
- •
Tungiasis is associated with not wearing closed-toe footwear and dirt floors
Tungiasis is an ectoparasitic disease caused by skin penetration by the female Tunga penetrans or, less commonly, Tunga trimamillata flea.122 It is endemic in Latin America, the Caribbean, and sub-Saharan Africa123 and occurs in travelers returning from
References (189)
- et al.
Human louse-transmitted infectious diseases
Clin Microbiol Infect
(2012) Scabies and Pediculosis
Lancet
(2000)- et al.
The health of homeless people in high-income countries: descriptive epidemiology, health consequences, and clinical and policy recommendations
Lancet
(2014) - et al.
Severe iron deficiency anemia and lice infestation
J Emerg Med
(2011) - et al.
More than skin deep: severe iron deficiency anemia and eosinophilia associated with pediculosis capitis and corporis infestation
JAAD Case Rep
(2019) The centenary of the discovery of trench fever, an emerging infectious disease of World War 1
Lancet Infect Dis
(2016)- et al.
Outbreak of epidemic typhus associated with trench fever in Burundi
Lancet
(1998) - et al.
The epidemic typhus and trench fever are risk for public health due to increased migration in southeast of Turkey
Acta Trop
(2018) - et al.
Pathogenicity and treatment of Bartonella infections
Int J Antimicrob Agents
(2014) - et al.
Louse-borne relapsing fever among East African refugees in Europe
Trav Med Infect Dis
(2016)
Fourth case of louse-borne relapsing fever in Young Migrant, Sicily, Italy, December 2015. Mini Review Article
Public Health
Infectious disease profiles of Syrian and Eritrean migrants presenting in Europe: a systematic review
Trav Med Infect Dis
Detection of relapsing fever in human blood samples from Israel using PCR targeting the glycerophosphodiester phosphodiesterase (GlpQ) gene
Acta Trop
Comparison of antibiotic regimens for treating louse-borne relapsing fever: a meta-analysis
Trans R Soc Trop Med Hyg
Outbreak of epidemic typhus in Russia
Lancet
Epidemic typhus
Lancet Infect Dis
Epidemic of louse-borne relapsing fever in Ethiopia
Lancet
Fomite transmission in head lice
J Am Acad Dermatol
Dermoscopy for diagnosis of pediculosis capitis
J Am Acad Dermatol
No evidence of Bartonella quintana but detection of Acinetobacter baumannii in head lice from elementary schoolchildren in Paris
Comp Immunol Microbiol Infect Dis
Bartonella quintana in Ethiopian lice
Comp Immunol Microbiol Infect Dis
Human head lice and pubic lice reveal the presence of several Acinetobacter species in Algiers, Algeria
Comp Immunol Microbiol Infect Dis
Permethrin and malathion resistance in head lice: results of ex vivo and molecular assays
J Am Acad Dermatol
Evidence that head and body lice on homeless persons have the same genotype
PLoS One
Body lice.
Arthropod-borne diseases associated with political and social disorder
Annu Rev Entomol
Global output of research on epidermal parasitic skin diseases from 1967 to 2017
Infect Dis Poverty
Preliminary report of body lice infesting homeless people in Brazil
Rev Inst Med Trop Sao Paulo
Risk factors for human lice and bartonellosis among the homeless, San Francisco, CA, USA
Emerg Infect Dis
Prevalences of scabies and pediculosis corporis among homeless people in the Paris region: results from two randomized cross-sectional surveys (HYTPEAC study)
Br J Dermatol
Changing demographics and prevalence of body lice among homeless persons, Marseille, France
Emerg Infect Dis
The prevalence of mental disorders among the homeless in Western countries: systematic review and meta-regression analysis
PLoS Med
“Human tragedy”: LA homelessness jumps to record-breaking level.
The 2017 Annual Homeless Assessment Report (AHAR) to Congress, part 1: point-in-time estimates of homelessness.
Homelessness is a tragedy the U.S. can afford to fix. Bloomberg.
Third overview of housing exclusion in Europe 2018.
An unusual autopsy case of lethal hypothermia exacerbated by body lice-induced severe anemia
Int J Leg Med
Bartonella quintana, past, present, and future of the scourge of World War I
APMIS
Bartonella (Rochalimaea) quintana bacteremia in inner-city patients with chronic alcoholism
N Engl J Med
Epidemiological studies on Bartonella quintana infections among homeless people in Tokyo, Japan
Jpn J Infect Dis
Bartonella quintana and urban trench fever
Clin Infect Dis
Bartonella quintana in body lice from scalp hair of homeless persons, France
Emerg Infect Dis
Bartonella quintana and typhus group Rickettsiae exposure among homeless persons, Bogota, Colombia
Emerg Infect Dis
Body lice of homeless people reveal the presence of several emerging bacterial pathogens in northern Algeria
PLoS Negl Trop Dis
Cutaneous bacillary angiomatosis in renal transplant recipients: report of three new cases and literature review
Transpl Infect Dis
Cutaneous bacillary angiomatosis due to Bartonella quintana in a renal transplant recipient
Transpl Int
Culture of Bartonella quintana and Bartonella henselae from human samples: a 5-year experience (1993 to 1998)
J Clin Microbiol
Bacillary angiomatosis and bacillary peliosis in patients infected with human immunodeficiency virus
Clin Infect Dis
Louse-borne relapsing fever in Ethiopian children: experience of a rural hospital
Trop Doct
Outbreak of louse-Borne relapsing fever among urban dwellers in Arsi Zone, central Ethiopia, from July to November 2016
Am J Trop Med Hyg
Cited by (0)
Funding sources: None.
Dr Chosidow has received research support from Merck Sharp & Dohme. Drs Coates, Thomas, Engelman, and Chang have no conflicts of interest to disclose.
Date of release: March 2020
Expiration date: March 2023