Meningococcal Carriage Among Hajjis in Makkah, 1421 H

Meningococcal meningitis is a major health risk both in developed as well as developing countries, especially under crowded conditions. [1] Every year approximately two million pilgrims from over 140 countries gather in Saudi Arabia to perform Hajj. In recent years, a number of outbreaks related to Hajj have been reported. Approximately 400 cases of meningococcal disease caused by N. meningitides serogroup W135 were identified worldwide related to Hajj 1420 H (2000 G).[2] The Saudi Arabian government requires all pilgrims to be vaccinated against Meningococcal meningitis, however, vaccination does not protect against nasopharyngeal carriage of the bacteria, which is the primary source of infection. [3]

This study was conducted to estimate the N. meningitides carriage rate among pilgrims in the Pre and Post Hajj period of 1421 H. It was conducted among Hajjis arriving through King Abdul Aziz International Airport, Jeddah, using a descriptive longitudinal design.

Based on the endemic pattern of meningitis, Hajjis were stratified into three groups: the first group included Hajjis from endemic countries such as South Asian and African meningitis belt countries; the second group included Hajjis from non-endemic countries such as Malaysia, Indonesia, and Europe; and the third group comprised domestic hajjis. The estimated sample of 740 was allocated equally among the three groups. In the preHajj period, for the international Hajjis, six incoming flights were selected randomly. Forty-one Hajjis were selected randomly from each flight at passport check area. The same method of selection was applied to departing flights to recruit the posthajj sample. Regarding domestic Hajjis, three Hajj missions (Ham la) were randomly selected at King Khalid International airport in Riyadh, before traveling to Makkah. Eighty two Hajjis were selected from each mission. After performing Hajj rituals, a similar sample was selected from those three missions at the last day of camping in Mina. A structured questionnaire containing demographic data and vaccination status was filled by personal interview. A pharyngeal swab was taken from each Hajji for culture and typing of N. meningitides at Jeddah Regional Laboratory.

A total of 1458 Hajjis were included in the study, 715 pre-Haj and 743 post-Hajj. Males constituted 74.3% of pre-Hajj and 72.3% of post-Hajj sample. The study showed that there were 57 (8%) N. meningitides carriers in the pre-Hajj group. The carriage rate according to nationality was 21.3% among Indians, 20.5% among Bengalese, 11.1% among Sudanese, and only 3.4% among domestic hajjis. In the post-hajj group there were 77 (10.4%) carriers; the carriage rate was 53.0% among Malaysians, 7.7% among Indonesians, 6.7% among Bengalese, and 6.3% among Nigerians. Malaysians had the highest change in carriage rate (+51.3%), followed by Indians (-16.8%), Bengalese (-13.8%), Sudanese (-8.4%) and Indonesians (+6.4%) (Table I). Carriage rate increased with age, from 4% among those under 30 years old, to 11% among those aged 60 years and above pre-Hajj, with a similar pattern in the post-Hajj sample. There was no significant difference in carriage rate between genders.

Almost half (50.9%) of the pre-hajj N. meningitides isolates and 46.8% of the post-hajj isolates were nongroupable. Serotype W135 was among only 5.3% of pre-Hajj carriers, compared to 44.2% of post-Hajj isolates. For the B serotype, the percentage decreased from 15.8% to 3.9%, and for serotype X' from 14% to 3.9%. Serotypes A and Y were detected in 5.3% and 7% of pre-Hajj carriers, respectively, and were absent in posthajj sample. In the pre-Hajj sample, the risk of meningococcal meningitis carriage was 66% less among those vaccinated compared to non-vaccinated. However, in post-hajj, the risk of meningococcal meningitis carriage was 65% higher among those vaccinated compared to non-vaccinated. Both the decrease or increase in risk were not statistically significant.

Neisseria meningitides is a Gram-negative encapsulated diplococcus, with at least twelve sero-groups. Annually, it accounts for approximately 300,000 cases of bacterial meningitis and more than 30,000 deaths.[1] Although group A and C account for most epidemics, groups B and W-135 have been incriminated in recent years. Other serogroups are of little epidemiological significance. The disease is widespread in the so-called "meningitis belt" which covers sub-Saharan Africa, from Ethiopia in the east to Senegal in the west. In this area particularly, epidemic waves are seen every 8-14 years, killing many thousands of school children and young adults, often leaving survivors with serous lasting effects. [1,2] The most recent Meningococcal meningitis epidemic of 1996 has resulted in approximately 300,000 reported cases, the most affected countries were Nigeria, Niger, Burkina Faso, and Mali.[4] Humans are the main reservoir as cases or carriers and transmission is by direct contact, including respiratory droplets from nose and throat of infected persons. Transient nasopharyngeal carriage rather than disease is the normal outcome of Meningococcal colonization. Asymptomatic meningococcal carriers are the primary source of transmission of infection under both epidemic and endemic conditions. The risk of epidemic increases with the percentage of carriers in the population. [1,4] In countries with endemic disease, 5%-10% of the population may be asymptomatic carriers.[1,4]

The incubation period is 2-10 days, often 3-4 days during epidemics.[5] Meningococci usually disappear from the nasopharynx within 24 hours after institution of treatment with antimicrobial agents to which the organisms are sensitive. While vaccination is (90 €” 95%) effective in prevention of disease, it does not protect against nasopharyngeal carriage of the bacteria.[5]

The present study revealed that the Meningococcal carriage rate among pilgrims before and after Hajj was 8% and 10.4%, respectively. Pilgrims of India, Bangladesh, and African belt countries had the highest rate on their arrival, which corresponds to the endemic nature of the disease in these countries.[6] Southeast Asian countries Malaysia and Indonesia had a low carriage rate (2.6% and 1.3% respectively) on arrival to Makkah, which is in accordance with the non-endemic nature of the disease in these regions.[7]

Comparing pre and post Hajj carriage rates, this study showed a decrease in carriage rates among Indians, Bengalese, and African belt countries pilgrims, which may be the result of administration of chemoprophylactic drugs to pilgrims from endemic areas by the Saudi government. An increase of the carriage rate was seen among Malaysian and Indonesian pilgrims which indicate their exposure to meningococcal organism, especially WI35 serotype, during Hajj rituals. As compared to the other studies, W135 strain was one of the common serotypes found, especially after Hajj. W135 was not isolated from any of the domestic Hajjis in the pre and post Hajj periods, indicating that Saudi Hajjis are at equal risk of Contracting W135 infection and are not its source.

On the basis of this study, it is recommended that the Quadrivalent vaccine containing (A, C, Y, W135) should be given to all pilgrims in their home countries at least two weeks before their departure for Hajj. Chemoprophylactic drugs should be continued to all pilgrims from endemic countries on arrival and to all hajjis from non-endemic areas on departure, so as to prevent the global hajj related transmission of meningitis.

Table 2: Serotypes of meningococcal meningitis among carriers by nationality (pre & post hajj 1421 H)