Listeriosis
Acquired listeriosis
Listeriosis is an infection caused by the gram-positive bacterium Listeria monocytogenes. The infection is generally asymptomatic but can become extremely severe in immunocompromised patients, pregnant women and their foetuses/newborn and elderly. The severity of the disease is related to its invasiveness: if the infection is not invasive, it will generally cause mild or no symptoms and therefore no burden (with the exception of acute gastroenteritis if a person ingests a large amount of bacteria). Therefore, it is not surprising that most notified cases are invasive listeriosis diseases, hence complicated ones. In order to estimate the number of complicated cases we referred to the US Centers for Disease Controls 2012 and 2011 Listeriosis Annual Surveillance Summaries (CDC, 2014), reporting 9597% of cases as invasive, and we applied this to the proportion of complicated symptomatic cases.
Manifestations of listeriosis are meningitis, septicaemia, pneumonia, and gastroenteritis. Based on reports from enhanced surveillance in the Netherlands (Doorduyn, 2006 a,b) and a Gamma distribution used to express the uncertainty, Kemmeren et al. (Kemmeren, 2006) and Haagsma et al. (Haagsma, 2009) estimated the distribution of these health states for acquired listeriosis. However, from a clinical perspective it is conceivable that most cases present a mixed form of the disease and isolates are available from multiple anatomical sites. We therefore defined symptomatic infections as either complicated (invasive) or uncomplicated.
In order to determine those long-term sequelae which are linked only to the manifestation of meningitis, we looked at enhanced surveillance in a few European countries, however data on the risk of developing meningitis during invasive listeriosis disease was inconsistent. Therefore, we referred to CDC enhanced surveillance in the USA from 2007 to 2012 and estimated that 1318% of invasive (complicated) symptomatic cases would present with meningitis (CDC, 2014).
In the current model, the age-specific case fatality proportion related to listeriosis is derived from cases of acquired listeriosis notified to TESSy from 2009 to 2013 (see Table 3) by all EEA Member States except Bulgaria and Lithuania because they report only aggregate data. The case fatality proportion is applied to complicated cases only.
Perinatal listeriosis
Perinatal listeriosis encompasses both pregnant women and their foetuses or newborns. Of the pregnant women with listeriosis, around two out of three will present with prodromal influenza-like symptoms such as fever, chills and headache. Three to seven days after the prodromal symptoms, the pregnant woman may abort the foetus or have premature labour (Gellin, 1989). To the mother, listeriosis is rarely life-threatening, however, infection in the first trimester of pregnancy may result in spontaneous abortion and, in later stages, in stillbirth or a critically ill newborn (Farber, 1991a). Newborns may present with an early-onset or a late-onset form of listeriosis. Early-onset listeriosis is defined as a case of symptomatic listeriosis in a newborn that is less than seven days old. Early-onset listeriosis is acquired by the foetus prenatally. Newborns with early-onset listeriosis mostly develop sepsis and meningitis (Farber, 1991b; Mylonakis, 2002). Late-onset listeriosis is defined as symptomatic listeriosis in a newborn during the first eight to 28 days of life. In this case, the unborn child is infected during childbirth when passing through the birth canal. Newborns with late-onset listeriosis are usually born healthy and at full term, but are at higher risk of developing meningitis during their first weeks of life (Farber, 1991a).
In the current study, the disease burden for health outcomes of early- and late-onset listeriosis are combined into one category. Based on data reported to TESSy between 2009 and 2013, the case fatality proportion was set to 18.71%.
Risk of complications
Long-term sequelae due to meningitis may occur, and will therefore be considered in the outcome tree. The frequency of other post-infectious complications following listeriosis is low (Haagsma, 2009) and therefore they have been disregarded in the current study.
According to Aouaj et al. (Aouaj, 2002), 20% of all listeriosis cases in their study are perinatal. Therefore, of the 147 cases analysed for long-term outcomes (Aouaj, 2002), we estimated that there were 118 acquired cases (29 perinatal). The study stated that 15 (12.7%) of the total number of acquired listeriosis cases presenting meningitis developed neurological long-term sequelae.
Given that 1318% of all acute cases present meningitis, the risk of developing neurological long-term sequelae from all cases of complicated acquired listeriosis is 1.652.29%.
Similarly, knowing that seven of the 29 perinatal listeriosis cases (24%) developed long-term neurological sequelae and that all acute cases present meningitis, the risk of developing life-long neurological disabilities from a perinatal listeria infection is 24%.
Model input summary
Table 1. Transition probabilities and distributions used in the outcome tree
Health outcome |
Distribution of health states in health outcome |
Transition probability |
Source/assumption |
Acquired listeriosis |
|||
Symptomatic infection (Uncomplicated) (Complicated) |
35% |
|
CDC, 2014 |
Fatal cases |
|
Age dependent |
TESSy 20092013 |
Permanent disability following meningitis |
|
1.652.29% of complicated cases |
Aouaj, 2002; CDC 2014 |
Perinatal listeriosis |
|||
Fatal cases |
|
18.71% |
TESSy 20092013 |
Permanent disability due to meningitis |
|
24% |
Aouaj, 2002 |
Table 2. Disability weights and duration
Health outcome |
Disability Weight (DW) (Haagsma, 2015) |
|
Duration |
||
DW |
Label |
In years |
Source |
||
Acquired listeriosis |
|||||
Symptomatic infection (Uncomplicated) (Complicated) |
0.149 (0.120.182) |
Diarrhoea, moderate |
0.020.5 |
Kemmeren, 2006 |
|
Permanent disability following meningitis |
0.0110.421 |
From lowest to highest motor and cognitive difficulties |
Remaining life expectancy |
|
|
Perinatal listeriosis |
|||||
Symptomatic infection |
0.655 (0.5790.727) |
Intensive care unit admission |
0.020.5 |
Kemmeren 2006 & Haagsma 2009 |
|
Permanent disability due to meningitis |
0.0110.421 |
From lowest to highest motor and cognitive difficulties |
Remaining life expectancy |
|
|
Table 3. Age-group acquired listeriosis case fatality proportion based on cases and deaths notified to TESSy (20092013)
Age groups |
% |
0 |
11.90 |
1-4 |
0.00 |
5-9 |
5.88 |
10-14 |
20.00 |
15-19 |
13.16 |
20-24 |
1.75 |
25-29 |
4.10 |
30-34 |
1.39 |
35-39 |
8.40 |
40-44 |
12.50 |
45-49 |
14.08 |
50-54 |
16.59 |
55-59 |
13.77 |
60-64 |
18.16 |
65-69 |
15.65 |
70-74 |
15.17 |
75-79 |
17.83 |
80-84 |
17.35 |
>85 |
23.15 |
All ages |
15.74 |
References
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CDC (2014). Centers for Disease Control and Prevention, National Surveillance of Bacterial Foodborne Illnesses (Enteric Diseases) National Listeria Surveillance. Available at: http://www.cdc.gov/nationalsurveillance/listeria-surveillance.html [accessed 2 October 2014].
Doorduyn Y, de Jager CM, van der Zwaluw WK, Wannet WJ, van der Ende A, Spanjaard L, et al. (2006a). Invasive Listeria monocytogenes infections in the Netherlands, 1995-2003. Eur J Clin Microbiol Infect Dis, 25(7):433-442.
Doorduyn Y, de Jager CM, van der Zwaluw WK, Wannet WJ, van der Ende A, Spanjaard L, et al (2006b). First results of the active surveillance of Listeria monocytogenes infections in the Netherlands reveal higher than expected incidence. Euro Surveill, 11(4):E060420 060424.
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Mylonakis E, Paliou M, Hohmann EL, Calderwood SB, Wing EJ. (2002). Listeriosis during pregnancy: a case series and review of 222 cases. Medicine (Baltimore), 81(4):260-269.