Lecture 7 Meningococcal & Pertussis Infections PDF

By Dr: Samah Saleh El-Hadidy  Droplet infections Viral Bacterial Influenza Measles TB Mumps Meningitis Rubella Streptococcus Coronaviruses  MEMNINGOCOCCAL MENINGITIS  It is an acute infectious bacterial disease characterized...

By Dr: Samah Saleh El-Hadidy  Droplet infections Viral Bacterial Influenza Measles TB Mumps Meningitis Rubella Streptococcus Coronaviruses  MEMNINGOCOCCAL MENINGITIS  It is an acute infectious bacterial disease characterized by purulent meningitis  Epidemiology and magnitude of the problem:  Epidemics occur irregularly every 10 years.  In endemic areas, 5-10% of population are asymptomatic carriers.  The greatest incidence occurs in winter and spring  Large epidemics occur in hot dry regions especially Mid- African countries which are known as (The meningitis belt). Early outbreaks can be expected when:  There is an increase of (2-3) times the incidence of the disease compared to the same time period in the Previous 3-5 years  Cases double week after week over a period of 3 weeks  The infection rate is 5 per 100,000 population Nationally (in Egypt):  In 2007, the vaccination policy in Egypt was modified to include giving the quadruple vaccine (ACYW135) for gatherings, such as, the army, police, prisons, pilgrim's camps, and this led to a decrease in the number of cases and the absence of any epidemic outbreak since that time A Case definition ) Suspected case: A case that meets the clinical case definition  Sudden onset of fever (>38.5C) + one or more of the following:  Stiff neck, Altered consciousness  Other meningeal signs or petechial rash  N.B. Below 1 year suspect meningitis if there is fever & bulging fontanel. B) Confirmed Case:  A suspected case with positive culture of CSF. Causative agents:  Neisseria meningitidis (the meningococcus :, a Gram-negative aerobic diplococcus)  Various serogroups have been recognized including groups A, B, C, W135, X, Y and Z. Reservoir:  Cases : represent very minor role in transmission of infection.  Carriers:  The most important source of infection in the endemic areas, they represent 5-10% of the normal population, having organisms in their nasopharynx during the inter-epidemic period.  When the carrier rate increase, it means threatened epidemics and during epidemics the carrier rate may increase to be to 70-80% of population.  Exit  Period of infectivity?????????????  Mode of transmission:  Direct transmission: (main mode) direct droplet, in case of direct contact with carriers or cases.  Indirect transmission: (minor role) Vehicle-borne: contaminated articles.  Rarely air born.  Portal of entry  Incubation period 2 -7 days  Susceptibility and resistance:  Age Occurs usually in children and young adults, during epidemics it may affect any age  Sex  Immunity: There is no maternal immunity. high ratio of carriers leads to repeated subclinical infection, moderate or high level of immunity. Vaccination gives high level of immunity > 3 years.  Environmental factors: . The greatest incidence occurs in winter and spring. Epidemics in adults commonly occur in confined communities under overcrowded living condition such as military camps, and institutes. The risk in household contacts is 500 to 800 times higher than in the general population. Epidemics usually having a secular trend every 10 years  Prevention: I.General prevention:  Good ventilation & prevention of overcrowding especially in schools, work places, dormitories & hospitals.  Education of the public to ↓ direct contact & exposure to droplet infection.  II. Specific prevention: A) Active immunization: 1. Quadrivalent vaccine containing group A, C, Y & W 135: Nature,Dose, Indications:  Adult & older children, military troops & camps.  In Egypt, it is given to school children at the age of 6 & 9 years 2. Vaccine containing group A:  For children 3 months-2 years  2 doses 0.5 ml S.C injection 3 months apart. 3.Vaccine containing group A & C: for adult & old children (B) Chemoprophylaxis:  Rifampicin:  Ciftriaxone:  Ciprofloxacin  Control: I. Case: 1.Notification to local health office. 2. Isolation at fever hospital. 3. Treatment: started immediately & before isolation of the organisms.  Antibiotics: parenteral penicillin (the drug of choice), ampicillin or chloramphinicol.  It should continue 5 days after fever ends & CSF picture becomes normal.  Symptomatic treatment. 4. Disinfection. 5. Release after 24 hours from starting treatment. II. Contacts: - Enlistment age, sex, vaccination history. - Surveillance for early signs to start treatment without delay. - Chemoprophylaxis. III epidemic measures 1. Surveillance: early diagnosis & immediate treatment of suspected case. 2. Raising awareness of the disease among health service providers 3. Maintain a backup stock of vaccines, equipment and basic supplies 4.Prepare an emergency response plan 5. Mass vaccination when an epidemic is detected. is better to vaccinate the entire population but In case of insuffient resources Focusing on high-risk age areas.  Pertussis Definition: Pertussis, also known as whooping cough, is a highly contagious respiratory infection characterized by a paroxysmal cough. Pertussis remains a significant cause of morbidity and mortality in infants younger than 2 years. Global situation: In 2018, there were more than 151 000 cases of pertussis globally. National situation: No cases were reported in Egypt since 2002.  Causative agent ; the bacterium Bordetella pertussis  Reservoir : human case is the only reservoir(no carrier state)  Infective material : nasopharyngeal and bronchial secretions  Susceptibility (host risk factors):  Age : it’s a disease of infants and preschool children the highest incidence below 5 years. Infants are susceptible to infection from birth because no Maternal immunity is transmitted.  Gender : incidence and fatality are more among female than male children  Environmental factors:  pertussis occurs throughout the year but shows seasonal trend and more cases occur in winter and spring why???  Low socioeconomic standards increase the risk of pertussis.  Immunity : is good after adequate immunization and following recovery of infection.  Carriers and immunity?  Modes of transmission: - Main mode of transmission: Direct droplet and direct contact - -Vehicle-borne : Freshly contaminated articles and fomites may play a role. I.P. : 6 - 20 days  Prevention A. General prevention: Health education. Health promotion. Sanitary environment: good ventilation , avoid overcrowding , B. Specific prevention: I. Active immunization: 1. Pertussis killed vaccine: (In Egypt : compulsory in Penta vaccine at 2,4,6 months of age and in DPT booster dose at 18 months). In 2021, immunization against DPT for Egypt was 96 %. DPT Vaccination is contraindicated in: - History of epilepsy or any neurological disorders. - If the first dose is associated with convulsions. - Children > 4 years old, as it may lead to anaphylactic reactions or encephalopathy 2. Acellular pertussis vaccine: -DTaP : Given for children 6 weeks through 6 years. The DTaP vaccine contains full-strength doses of all three vaccines -Tdap : Given for children age 7 and adults. It contains less amount of diphtheria toxoid & acellular pertussis antigen than DTaP. All adults who have never received one should get a shot of Tdap. All adults who have never received one should get a shot of Tdap. II. Seroprophylaxis : has low efficiency in disease prevention. III. Chemoprophylaxis: Erythromycin for 14 days to close contacts  Control: a-Cases: Early case finding Notification to local health office: immediate Isolation at fever hospital or home(as highly infectious early in disease). Treatment: According to treating physician guidelines. Concurrent and terminal disinfection. Release after 5 days of starting antimicrobial therapy. b-Contacts: Enlistment age, sex, vaccination history. Surveillance for maximum IP. Contacts under 4 years of age who are fully vaccinated, should be given booster dose of vaccine as soon as possible. For contacts more than 4 years or not vaccinated, acellular pertussis vaccine & hyperimmunoglobulin are given with a course of erythromycin for 14 days. 