Meningitis

Disease Overview

Key Facts

Overview

Generalities

Agents

Several agents:

1) Bacteria:
- Neisseria meningitides (meningococcus): the serotypes responsible of invasive infection are A, B, C, W135, Y, X
- Haemophilus influenza: there are 6 serotypes from (a) to (f). The serotype (b) is responsible of invasive infection
- Streptococcus pneumonia (pneumococcus): there are more than 90 serotypes
- Other bacterial agents: listeria, staphylococcus, enteric bacteria, group B streptococci, tuberculosis …

2) Virus:
- Mumps
- Measles
- West Nile virus: a flavivirus
- Enterovirus: including Coxsackieviruses A (1-11, 14, 16-18, 22, 24), Coxsackieviruses B (1-6), Echoviruses (1-7, 9-23, 25, 27, 30-33), Enterovirus 71, Poliovirus (1-3)
- Herpes Simplex virus: with 2 types 1 and 2
- Varicella / Chicken-pox: Human (alpha) herpesvirus 3 (varicella-zoster) from the group Herpesvirus
- Adenovirus: Adenovirus, several types (1, 2, 3, 4, 5 and 7), genus Mastadenovirus, family Adenoviridae,
- Lymphocytic choriomeningitis: lymphocytic choriomeningitis virus (arenavirus)
- Sandfly fever viruses: genus phlebovirus, family Bunyaviridae. They include more than 60 antigenically distinct virus serotypes. Two main groups are identified: the sandfly fever group including the Naples serocomplex (Karimabad virus, Arabia virus, Massilia virus, Punique virus, Tehran virus, Toscana virus …) and Sicilian serocomplex; and the Uukuniemi group.

-Other virus: arboviruses…

3) Parasites and fungi:
- Leptospirosis: Spirochetes, Leptospira interrogans (25 serogroups)
- Other: Candida albicans, cryptococcal, syphilis …

Incubation

The incubation varies with the agent.

Agent	Incubation
Bacteria
Neisseria meningitidis	3-4 days (2-10 days)
Haemophilus influenza	2-4 days
Streptococcus pneumoniae	1-4 days
Listeria monocytogenes	3-70 days (median of 3 weeks)
Virus
West Nile virus	3-12 days
Enterovirus	7-14 days (2-35 days)
Herpes	2-12 days
Varicella / Chicken-pox	2-3 weeks
Lymphocytic choriomeningitis virus	8-13 days (15-21 days for meningitis)
Adenovirus	1-10 days
Sandfly fever viruses	3-4 days (up to 6 days)
Parasites and Mycoses
Leptospira	2-30 days (10 days)

Period of communicability

The period of communicability varies with the agent.

Agent	Period of communicability
Bacteria
Neisseria meningitidis	From onset and up to 24 hours after starting antibiotherapy that has effective concentrations in nasopharynx.
Haemophilus influenza	From onset and up to 24-48 hours of starting effective antibiotherapy.
Streptococcus pneumoniae	As long as the bacteria is present in the upper respiratory tract.
Listeria monocytogenes	- Mothers of infected newborns can shed the bacteria in vaginal discharges and urine 7-0 days after delivery - Infected patients can shed the bacteria in stool for several months
Virus
West Nile virus	No person-to-person transmission.
Enterovirus	- Virus excreted in stools for several weeks - Virus excreted in pharynx for the first 2 weeks post infection
Herpes	2-7 weeks after skin lesions onset.
Varicella / Chicken-pox	2 days before until the skin lesions are crusted (5 days).
Lymphocytic choriomeningitis virus	No person to person transmission.
Adenovirus	Shortly prior to and for the duration of the active disease
Sandfly fever viruses	Virus present in blood of infected patients 1 day before and 1 day after onset of illness.
Parasites and Mycoses
Leptospira	Excreted in urine for 1 month

Reservoir

The reservoir varies with the agent.

Agent	Reservoir
Bacteria
Neisseria meningitidis	Humans
Haemophilus influenza	Humans
Streptococcus pneumoniae	Humans, possible carriage.
Listeria monocytogenes	Soil, forage, water, mud and silage.
Virus
West Nile virus	Birds
Enterovirus	Humans
Herpes	Humans
Varicella / Chicken-pox	Humans
Lymphocytic choriomeningitis virus	House mouse (Mus musculus), hamster colonies. The mouse excretes the virus in saliva, feces and urine.
Adenovirus	Humans
Sandfly fever viruses	Humans, rodents.
Parasites and Mycoses
Leptospira	Wild and domestic animals

Modes of transmission

The modes of transmission vary with the agent.

Agent	Modes of transmission
Bacteria
Neisseria meningitidis	Person to person transmission: direct contact with droplet, nasal and throat discharge
Haemophilus influenza	Person to person transmission: direct contact with respiratory, nasal and throat discharge.
Streptococcus pneumoniae	Person to person transmission: direct contact with respiratory discharge
Listeria monocytogenes	- Food-borne: ingestion of raw or contaminated milk, soft cheese vegetables and ready-to-eat meats (Pate) - Direct contact with infectious material - Neonatal: from mother to fetus or from mother to newborn (through the infected birth canal) - Nosocomial transmission in nursery: via contaminated equipment or material
Virus
West Nile virus	Bite by infected mosquitoes (Culex sp, or Anophele sp)
Enterovirus	- Person-to-person: - Fecal-oral - Contact with respiratory secretions - Contact with conjunctival secretions - Contaminated water / swimming pools - Flies
Herpes	- Person-to-person: - Contact with saliva - Sexual contact - Soiled hands - Neonatal (infected birth canal)
Varicella / Chicken-pox	- Person-to-person: - Contact with droplets - Contact with vesicle fluid - Indirect contact - Airborne
Lymphocytic choriomeningitis virus	- Airborne: contaminated dust - Food-borne: ingestion of contaminated food - Direct contact: skin contamination or cuts
Adenovirus	- Person-to-person: - Fecal-oral route - Respiratory transmission - Inoculation with conjunctival secretions - Nosocomial - Contaminated water and swimming pools
Sandfly fever viruses	Bite of infective phlebotomine (Phlebotomus papatasi, P. perfiliewi , P. perniciosus, P. major sensu lato )
Parasites and Mycoses
Leptospira	- Contact with abraded skin or mucous membranes with soil, vegetation, contaminated with urine of infected animals or contaminated water - Direct contact with urine or tissues of infected animals - Ingestion of food or water contaminated with urine of infected animals

Clinical

The symptoms vary with the agent.

Agent	Clinical picture
Bacteria
Neisseria meningitidis	Meningitis, septicaemia
Haemophilus influenza	Meningitis, epiglottitis, pneumonia …
Streptococcus pneumoniae	Meningitis, pneumonia, septicaemia
Listeria monocytogenes
Virus
West Nile virus	- Usually asymptomatic. - Complication: meningitis and encephalitis
Enterovirus	- Asymptomatic, - Gastro-enteritis, flu-like illness, aseptic meningitis, paralysis
Herpes	- Gingivostomatitis (type1), genital infection (type 2) - Complications: meningoencephalitis - Reactivation is possible
Varicella / Chicken-pox	- Skin eruption: first maculo-papular then vesicular. - Complications: pneumonia, hemorrhage, meningoencephalitis
Lymphocytic choriomeningitis virus	- Influenza-like illness. - Complications: meningitis, parotiditis, arthritis, myocarditis…
Adenovirus	- Epidemic herato-conjunctivitis, gastro-enteritis, pharyngo-conjunctival fever, acute respiratory infection - Complications: meningoencephalitis
Sandfly fever viruses	- Usually self-limited disease: fever, myalgia, headache, photophobia … - Complications: Aseptic meningitis and meningoencephalitis (Toscana),
Parasites and Mycoses
Leptospira	Rash, hemolytic anemia, hemorrhage, hepato-renal failure, mental confusion, myocarditis…

Worldwide

Agent	Profil
Bacteria
Neisseria meningitidis	Endemic in the African meninigitis belt (from Senegal to Ethiopa)
Haemophilus influenza	Worldwide under 5 years
Streptococcus pneumoniae	Worldwide
Listeria monocytogenes	Worldwide
Virus
West Nile virus	Widespread in Africa, Middle East, North America, India.
Enterovirus	Worldwide
Herpes	Worldwide
Varicella / Chicken-pox	Worldwide
Lymphocytic choriomeningitis virus	America, Europe.
Adenovirus	Worldwide
Sandfly fever viruses	In Mediterranean counties, Europe and Middle East
Parasites and Mycoses
Leptospirose	Worldwide

Lebanon

The annual average of reported cases of meningitis is 192.
Among them, meningitis due to Neisseria meningitis occurs with 6 (2-12) cases per year.
Among them, meningitis due to Haemophilus influenza occurs with 1 (0-2) cases per year.
Among them, meningitis due to Streptococcus pneumoniae occurs with 19 (16-21) cases per year.

Control objective

Control