A Severe Epidemic of Meningococcus Meningitis in Chile, 1941-1942

Control of group C meningococcal disease in Australian aboriginal children by mass rifampicin chemoprophylaxis and vaccination

An outbreak of 12 cases of meningitis, 11 caused by Neisseria meningitidis serogroup C, occurred at Doomadgee from September, 1990, to April, 1991. The incidence of meningitis was 17.55/10(3) person-years. Only children aged 1-10 years were affected. In October, 1990, or shortly thereafter, 473/509 children aged between 1 and 15 years inclusive had one dose of Mencevax AC. From the time of vaccination until April, 1991, a further eight cases occurred, six in vaccinated children. Vaccine efficacy in 1-15 year olds was calculated as 77%. Despite this, in April, 1991, the prevalence of antibody to group C polysaccharide in vaccinated children (78%) was not significantly different from that in unvaccinated children and adults. 46 nonresponders were revaccinated, and, in February, 1992, 78% had antibodies to group C polysaccharide. In April, 1991, an estimated 3.0% of the population had group C organisms, carriage being directly related to household crowding. In June, 1991, 2 months after mass prophylaxis with rifampicin, none of these individuals were carriers. In October, 1991, the carriage rate of group C organisms was 0.64%. There have been no further cases caused by the epidemic strain. Although uncrowded housing is a basic need, mass chemoprophylaxis and two doses of vaccine for children should be used in similar outbreaks.

Epidemic meningococcal meningitis in central Australia, 1987-1991

OBJECTIVE

To describe an outbreak of meningococcal meningitis and the impact of rifampicin chemoprophylaxis on secondary attack rates among Aboriginal people in central Australia.

DESIGN

Prospective study of patients admitted to hospital between September 1987 and May 1991.

SETTING

The Alice Springs Health Region of the Northern Territory and the Anangu Pitjantjatjara Lands of South Australia, covering a population of 13,228 Aboriginal people.

SUBJECTS

Patients admitted to the Alice Springs Hospital with clinical signs or autopsy findings of meningococcal disease. Rifampicin chemoprophylaxis was given to close contacts of all cases. Mencevax AC vaccine was offered to children aged 1 to 15 years in the Region.

MAIN OUTCOME MEASURES

Blood or cerebrospinal fluid (CSF) with Neisseria meningitidis, or a positive result of latex agglutination testing on CSF. Positive isolates were serogrouped.

RESULTS

Seventy-seven cases of meningococcal disease were diagnosed in Aboriginal people over four years compared with one to two cases per year previously; of these, 60 were definite, 7 probable and 10 suspected cases. Seventy-six subjects had meningitis, of whom one also had the clinical features of meningococcal septicaemia; one other subject had positive blood cultures with a mild febrile illness without features of meningitis. The annual attack rate of meningococcal disease in the Aboriginal population was 1.6/1000. The relative risk for secondary cases was estimated to be between 0.3 (95% confidence interval [CI], 0.09-0.92) and 0.5 (95% CI, 0.15-1.53). The annual attack rate in the non-Aboriginal population was 0.04/1000.

CONCLUSIONS

The epidemic closely resembled those in sub-Saharan Africa, and in socioeconomically marginalised groups in developed countries. The relative risk for secondary cases was lower than generally reported, and was attributed to chemoprophylaxis for close contacts and the mass vaccination program for children. Until there are major improvements in living conditions, infectious diseases such as those transmitted by airborne droplets will continue to occur in Aboriginal communities.

Factors influencing susceptibility to meningococcal disease during an epidemic in The Gambia, West Africa

A study was made of factors that influenced susceptibility to group A meningococcal disease during an epidemic that affected The Gambia, West Africa during the dry season of 1982-83. No explanations were found for the distribution of cases between villages or within affected villages. Socio-economic status, crowding, nutrition and previous exposure to meningococcal disease all appeared to be unimportant. Examination of serum samples obtained before the outbreak from a few children who subsequently became patients and from an equal number of age-matched controls from the same village showed a higher mean serum IgA value in children who became patients than in controls. There were not, however, any significant differences found in the concentrations of IgG, IgM, complement or meningococcal antibody between the two groups. Four children who developed culture-proven group A meningococcal disease had raised titres of bactericidal antibody to the epidemic strain 2-3 months before their illnesses. Our findings suggest that some important risk factors for group A meningococcal disease remain to be identified.

Epidemic group C meningococcal meningitis in Upper Volta, 1979

Group C meningococci were isolated during an epidemic of meningococcal meningitis which occurred between January and May 1979 in eastern Upper Volta, an area previously associated with endemic and epidemic group A disease. A total of 539 cases of meningitis, 55 of which were fatal, were reported, giving an attack rate of 517 cases per 100 000 inhabitants. Attack rates were higher for children under 15 years of age. Clinical and bacteriological data suggested that the group C meningococci were sulfonamide-resistant. The last meningococcal epidemic in Upper Volta occurred in 1970 and was nationwide. Epidemic cycles of group A meningococcal meningitis have occurred at 10-15 year intervals in the sub-Saharan region, raising concern that the current increase in activity may presage more wide-spread disease in the next dry season.

Meningococcal disease in Belgium. Secondary attack rate among household, day-care nursery and pre-elementary school contacts

During a recrudescence of meningococcal disease mainly due to serogroup B, 1913 notified cases were investigated in Belgium from 1971 to 1976. From 1971 to 1973, 76 secondary cases were reported out of a total of 1455 cases (5.2 per cent); and from 1974 to 1976, nine secondary cases were reported of a total of 458 cases (2.0 per cent). Seventy per cent of the secondary cases occurred within seven days after the Index case. The 4.7 per cent fatality rate among secondary cases was lower than the 9.8 per cent fatality rate among primary cases. The estimated secondary attack rate was 685 per 100 000 among household contacts, 404 per 100 000 among day-care nursery contacts and 77 per 100 000 among pre-elementary school contacts. These attack rates were significantly higher (P less than 0.001) than the incidence rates in the corresponding age-groups in the general community, indicating the need for prophylaxis in these contacts.

Prevention of secondary cases of meningococcal disease in household contacts by vaccination

Household contacts of patients with group A meningococcal infection were vaccinated with either meningococcal vaccine or tetanus toxoid. Five of the 523 subjects who received tetanus toxoid developed meningococcal meningitis and another four probably had meningococcal disease. Only one possible case of meningococcal infection occurred among 520 contacts vaccinated with meningococcal vaccine. Vaccination had no effect on nasopharyngeal carriage of meningococci. Vaccination of household contacts of patients with group A meningococcal infections is an effective way of using limited supplies of meningococcal vaccine, though its value would be limited in an epidemic. Secondary cases of meningococcal infection often occur within a few days of the index case, and, although vaccine alone seemed to provide adequate prophylaxis in these Nigerian subjects, additional chemoprophylaxis may be needed to cover this critical period.

An intercity outbreak of meningococcal meningitis in adults

An intercity outbreak of meningococcal meningitis occurred in five adults, with the acute onset of symptoms developing in two of the patients after they returned to Los Angeles from the San Francisco Bay area. The secondary attack rate was 36.4 percent in this entirely adult household. The authors review reports of secondary cases in civilian epidemics, as well as recommendations for chemoprophylaxis in household contacts.

Aspectos epidemiológicos da meningite meningocócica no município de São Paulo (Brasil), no período de 1968 a 1974

Estudo epidemiológico da meningite meningocócica no município de São Paulo no período de janeiro de 1968 a junho de 1974. A partir de julho de 1971 uma epidemia causada pelo meningococo sorogrupo C ocorreu na área. Em abril de 1974 foi observado o início de uma segunda epidemia determinada pelo meningococo sorogrupo A. Os maiores coeficientes de morbidade durante o período estudado ocorreram: nos meses frios; nos distritos sanitários da periferia do município; no grupo etário de 0 a 4 anos, no sexo masculino. No primeiro mês das duas epidemias diferiu significantemente o grupo etário mais atingido. A letalidade decresceu de 15,0% em 1968-1970 para 7,9% em 1971-1974. Ela apresentou, durante o período epidêmico, uma variação sazonal no sentido inverso ao da morbidade.

Bacterial meningitis in Navojo Indians

An analysis of 219 confirmed cases of bacterial meningitis among Navajo Indians during a 5-year period, July 1, 1968, through June 30, 1973, revealed that 56 percent were caused by Haemophilus influenzae, 26 percent by Neisseria meningitidis, 6 percent by Mycobacterium tuberculosis, and 6 percent by other organisms. The annual incidence of H. influenzae meningitis (17.7 per 100,000 persons) and that of pneumococcal meningitis (8.0 per 100,000) were much higher than the rates for these diseases reported from other population groups. The annual incidence of meningococcal meningitis (2.0 per 100,000) was similar to that found elsewhere. There was an ususual concentration of cases during the first year of life; 78 percent of H. influenzae, 64 percent of pneumococcal, and 50 percent of meningococcal meningitis occurred during this time. However, bacterial meningitis during the first month of life was not frequent (0.29 per 1,000 live births). Case fatality rates were similar to those reported for other population groups.

Control of cerebrospinal meningitis epidemics with sulfadimidine and penicillin; report on an experiment in mass chemoprophylaxis in the Sudan

Four villages in Kordofan Province of the Sudan were selected by the authors to determine the effectiveness of mass prophylactic treatment with sulfa drugs and penicillin in controlling cerebrospinal meningitis epidemics in rural areas with highly primitive living conditions. Sulfadimidine was given orally in two of the villages, and procaine penicillin G in oil with 2% aluminium monostearate (PAM) was given intramuscularly in the other two. The population of the villages was classified by age and by sex and given the following prophylactic doses: in Kaldung village, where 93% of the population was treated, 4 g of sulfadimidine were given to persons over 15 years of age, 2.5 g to those between 15 and 5, and 1.5 g to those under 5; in Korongo Abdulla, the same age-groups received 2.0 g, 1.0 g, and 0.5 g, respectively, and 34% of the population was treated; in El Machicha and Miri Bara villages, PAM was given to 38% and 90% of the respective populations in the dosage of 150,000 units to those over 15 years of age, 100,000 units to those between 15 and 5, and 75,000 to those under 5.In this campaign, some 4,000 people were examined daily and, where necessary, treated by a medical staff of four with five trained assistant dressers. The drugs had a noticeable influence on the number of cases in the protected groups, which showed an incidence of 4.86 cases per 1,000 of the total population of the 4 villages against 17.68 cases per 1,000 in the unprotected groups. The authors point out that in the Sudan it is not possible to take a neighbouring village as the control unit, since each village is an epidemic unit in itself and the results from treated and untreated would thus not be comparable. It was therefore decided to take that portion of the village population which did not receive treatment as the control series. The conditions under which the controls lived were, as regards environment and exposure to infection, strictly comparable to those of the treated persons. The results were similar with sulfa drugs and with penicillin.The authors conclude that mass chemoprophylaxis with sulfonamides or penicillin of populations living under primitive conditions is effective in the group treated, whatever the stage of the epidemic at the time of treatment, but that there is no reason to assume that it influences the development of the epidemic. There is no clear explanation why the groups protected did not become reinfected, but it is thought that this was perhaps due to the development of a low-grade immunity in previous carriers cleared by the prophylactic treatment.