Submit manuscript...
Journal of
eISSN: 2469 - 2786

Bacteriology & Mycology: Open Access


Received: January 01, 1970 | Published: ,

Citation: DOI:

Download PDF


In order to investigate the incidence of meningococcal meningitis in AL Nasiriya city, and to evaluate the effects of sociodemographic factors on infection, the current study involved collecting data from patients infected with Neisseria meningitides who attended in AL-Hussein Teaching Hospital in the periods of two years (beginning of 2015 to the end of 2016). The results showed that there are (219) patients infected with Neisseria meningitides. Of them, (112) cases (51.14%) have occurred during 2015, and (107) cases (48.86%) occurred during 2016. Our results also found that the infection was significantly higher in male than in females (P-value =0.0001), and in patients from the age group (44-66 years old). Seasonal variation was also seen in the occurrence of meningococcal meningitis infections during the study period. The present study concluded that meningococcal meningitis infections were influenced by sociodemographic factors, the infections appear to be dominant in the long warm seasons of Iraqi weather.

Keywords: meningitis, sociodemographic factors, neisseria meningitidis, seasonality


Meningitis is an inflammation of the meninges (the covering of the brain and spinal cord) caused by a variety of pathogenic organisms and continues to be an important source of morbidity and mortality.1 Meningitis can be caused by infection from bacteria as Neisseria meningitidis, Streptococcus pneumoniae, Haemophilus influenzae, Escherichia coli, Group B Streptococcus and viruses. Sometimes fungi, physical injury, cancer and drugs, but cases from these sources are rare. In general, meningitis caused by a virus is less serious than meningitis caused by bacteria.2 Neisseria meningitidis, a Gram-negative fastidious encapsulated aerobic diplococcus Colonies are positive by the oxidase test and most strains utilize maltose. The phenotypic classification of meningococci, based on structural differences in capsular polysaccharide, lipooligosaccharide (LOS) and outer membrane proteins, is now complemented by genome sequence typing (ST). Meningococcal meningitis is often serious and potentially fatal and death occurs on average in 10% of untreated patients.3 According to the World Health Organization (WHO), an estimated 500,000 cases and 50,000 deaths are attributed to N. meningitidis each year worldwide. Children and young adults are the main victims.4 The epidemiological profile of N. meningitidis is variable in different populations and over time and virulence of the meningococcus is based on a transformable/plastic genome and expression of certain capsular polysaccharides (serogroups A, B, C, W-135, Y and X) and non-capsular antigens. Although new vaccines hold great promise, meningococcal infection continues to be reported in both developed and developing countries, where universal vaccine coverage is absent and antibiotic resistance increasingly more common.5

The clinical features of meningitis are often non-specific and may overlap with those of other infections. About 90% of viral meningitis cases are due to common stomach viruses called enteroviruses, other viruses such as measles, herpes and West Nile is rare, but can be serious. Fungal meningitis is rarely infecting human, usually the result of spread of a fungus through blood to the spinal cord, and most common cause of fungal meningitis is Cryptococcus.6 Over 1.2 million cases of bacterial meningitis are estimated to occur worldwide each year and in 2002 meningitis caused an estimated 173000 deaths worldwide, most of them were children in developing countries.7 The current study aimed to describe the epidemiology of meningitis in Nasiriya city from the beginning of 2015 to the end of 2016, also, to find out the distribution of meningitis in terms of age and sex as well as to study the effect of seasonal variability on the incidence of meningitis.

Materials and methods

Data collection

The current study involved the data collection for patients with meningitis caused by Neisseria meningitidis who attended in AL-Hussein Teaching Hospital for in the periods of two years (beginning of 2015 to the end of 2016). The early detection of meningitidis was achieved by physician depending on the clinical presentation of symptoms. Confirmation of the infection was dependent on the results of cerebrospinal fluid (CSF) cultures in the laboratories which achieved using Vitek2 equipment and tools. Among the clinical details, the signs and symptoms at presentation such as stiff neck, headache, fever, altered mental state, seizures, and the treatment outcome were recorded. Demographic details such as age, sex and the month of presentation were also recorded. Statistical analyses. The data were analyzed, using SPSS soft wear package version 20. To find the variation in the prevalence during the period of study. Statistical significance was defined as a P-value <0.05. Statistical tests such as (percentage, Chi-square, LSD) were used for data analysis.


Our results found that the total number of patients diagnosed with meningitis that caused by N. meningitidis infection during two years (2015 and 2016) was (219) patients. Of them, (112) cases (51.14%) were occurred during 2015 and (107) cases (48.86%) occurred during 2016 as shown. It is clear that males were significantly high infected by meningitis than females (P value =0.0001) during the study period (two years as all). However, the percent of infection in male was higher, (26.9 % and 30.1 %) in 2015 and 2016 respectively, compared with that of females (24.2 % and 18.7%) in the same periods. This means that males might be at high risk to get meningitis infection than females. The results also found patients from the age group (44-66 years old) have the highest percent (33 % and 33.9%) of infection in both of 2015 and 2016 respectively, the second highest percent of infection were found in the patients from the age groups ( 1-9 years and more than 45 years old) in the year 2015 as it reached ( 24.10% for both), however, in the year 2016 the second highest percent of infection were found in patients form the age group ( 1-9 years old) as it reached (39.3%). Furthermore, patients age groups had significant prognostic effect and relation to complications of meningitis with p-value less than 0,05 in both of 2015 and 2016. In the same context, when percent of meningitis infection is compared according to the age groups of patients in both of 2015 and 2016, there are significant differences (P value = 0.008).

Seasonally, (36.50%) of meningitis infections have been reported in the summer (34.80 % in 2015 and 38.30 % in 2016). The frequency then decreased to (25.60%) in fall (24.10% in 2015 and 27.10% in 2016) followed by winter (24.20% total, 28.60% in 2015 and 19.60% in 2016) then spring which have the lowest percent of infection (13.70% total, 12.50% in 2015 and 15.00% in 2016). There were no significant differences in the occurring of meningitis infection according to the four seasons. Moreover, we found that males were highly affected by meningitis over all seasons of 2015 except the summer; also, meningitis infects patient aged between (20-44 years old) during all seasons of the same year except winter. However, these seasonal interactions of meningitis infection with age and sex are non-significant statistically during the year 2015. Likewise, in 2016 males were more infected than females in all of the four seasons, this result is non-significant statistically. Otherwise, percent of meningitis occurrence were increased significantly in patients aged between (1 – 9 years old) during both of autumn and summer of 2016 ( P value = 0.009) followed by patient from the age group (22 – 44 years old) whom were dominant in the infections that occurred during both of winter and spring. As a total comparison between the two years of study (2015 and 2016), showing no statistically significant differences in the occurrence of meningitis.


Bacterial meningitis is an important health problem worldwide, and despite advances in prevention and treatment, it remains a significant cause of morbidity and mortality in adults. The spread of this disease is related to deterioration and drop of environment, home and personal hygiene (8). The good early detection among hospitals make decrease in progression of the disease or death, and good immunization program helped to decrease outbreak of the disease. For the incidence of N. meningitidis in Iraq, Razak et al9 found that (4%) of Iraqi children suffering from meningitis were tested positive for N. meningitidis. Our results reported a higher incidence of meningitis in males (57.1%) than females (42.9%), this result agree with the study of Gurley et al.10 in 200910 in Bangladesh which showed that out of 1841 cases, 1307 were males, giving a male to female ratio of (2.5:1). It is likely that the underlying mechanisms that could explain these results would be multifactorial and include a complex interaction between social, behavioral, and biological factors. Females display more powerful cell-mediated and humoral immune responses to antigenic threats, such as infection and vaccination, than males, resulting in lower sensitivity to many infectious diseases.11 However; this improved immune response can also have harmful effects as a result of an inordinate inflammatory reaction.12

The results of the current study, found that patients from the age group (44-66 years old) and children have the highest percent meningitis infection resulted from N. meningitidis. These results are consistent with results of Doran et al.13 There are many factors of meningitis in general that can increase the risk of infection include: (age) infants and children are more risky than other age groups, (infectious trends) is trend to spread more quickly where larger groups of people gather together, (immune system) who had certain disease, medication, and surgical procedures that may weaken the immune system. However, N. meningitidis was the predominant pathogen for bacterial meningitis among children in Europe. Previous studies have identified that in recent years serogroup B N. meningitidis is responsible for the majority of meningococcal disease in Europe, while serogroup C is the most common in the US. The high frequency of bacterial meningitis cases due to N. meningitidis and S. pneumoniae come against the backdrop of the availability of vaccines for both pathogens.14Additionally, people with weak immune systems are more at risk for meningitis. Smoking, second-hand smoke and crowded living conditions also increase the risk for some kinds of meningitis. From the obtained results, we found that meningococcal meningitis occurrence varies significantly according to the four seasons of Iraqi weather, also significant differences were found between seasons according to ages and sexes of the patients during the study period. Generally, the highest percent of N. meningitis infection were happened in summer season followed by autumn then winter and finally spring where the lowest percent of meningococcal meningitis was occurred.

Seasonal variations are typical of meningococcal meningitis but may occur to a lesser extent with other agents of bacterial meningitis.15 The dry season in some countries such as Iraq is characterized by dust winds and cold nights. These conditions, combined with upper respiratory tract infections that damage the nasopharyngeal tract, are thought to lead to an increased risk of meningococcal disease. The dry season starting from June and reaching up till September has invariably been implicated in meningococcal epidemics.4 Nevertheless, in many parts of the world, the temporal patterns of bacterial meningitis including seasonality, inter-annual variability, and secular trends are poorly described. Therefore, several concerns remain about the disease's ecology. A comprehensive evaluation of the temporal dynamics of bacterial meningitis is the first, crucial step towards understanding the complex interactions between behavioral, cultural, social, immunological, and other factors that may drive these disease trends.16 On the other hand, results of other studies found that the incidence rates are highest during late winter and spring.17 The risk factors of meningitis include: lack of immunity to specific pathogens associated with young age, recent colonization with pathogenic bacteria, close contact (household, daycare center , college dormitories) with individuals having invasive disease caused by N. meningitidis, crowding, urban area ,poverty, Male gender , immunocompromised conditions (HIV, asplenia, complement deficiency, immunoglobulin deficiency, lymphocyte deficiency, malnutrition and malignancies) , penetrating head injuries, neurosurgical process and CSF leak.18,19


Meningitis was significantly associated with male sex, N. meningitidis patients significantly affects patients aged between (22 – 45 years old) as well as children (under 9 years old). Meningococcal meningitis occurrence is significantly associated with dry seasons (summer autumn) and the seasonality was affected by differences of age and gender of patients. The non-specific meningitis is increasing in number of cases dramatically since 2008 till now.

Conflicts of interest

All authors declare that there is no any conflict of interest.

Ethical clearance

Permission to conduct this study was issued by the Health institutional and the collection of Blood samples of individuals was carried out by under public health technician supervision.




  1. Thomas S Murray, Robert S Baltimore. Bacterial infections of the central nervous system. In: Colin D Rudolph, Abraham M Rudolph, editors. 22nd edition. Mcgraw Hill; 2011:913–919.
  2. Aya A, Mehmet G, Josoglu S et al. Characteristics of acute bacterial meningitis in southeast Turkey. 2004;58:327–333.
  3. Munguambe Alcides Moniz, António Eugénio Castro Cardoso de Almeida, Aquino Albino Nhantumbo, et al. Characterization of strains of Neisseria meningitidis causing meningococcal meningitis in Mozambique, 2014: Implications for vaccination against meningococcal meningitis. PloS one. 2018;13(8)e0197390.
  4. World Health Organization. Control of epidemic meningococcal disease. 2nd edn. Geneva, Switzerland: World Health Organization; 1998.
  5. Nadine G Rouphael, David S Stephens. Neisseria meningitidis: biology, microbiology, and epidemiology. Methods Mol Biol. 2012;799:1–20.
  6. Center for Disease Control and Prevention. Laboratory Methods for the Diagnosis of Meningitis Caused by Neisseria meningitidis, Streptococcus pneumoniae, and Haemophilus influenzae. 2nd edn. 2011.
  7. The World Health Report 2003. Shaping the future. Geneva. 2003.
  8. Saad Abdulrahman T, Nadir A Garjees, Aveen H Rasool. Antibiogram profile of septic meningitis among children in Duhok, Iraq. Saudi medical journal. 2017;38(5):517.
  9.  Razak Atheer, Harith JF Al-Mathkhury, Kifah A Jasim. Prevalence of Neisseria meningitidis in Iraqi children presented with meningitis. International Journal for Sciences and Technology. 2013;143(583):1–10.
  10. Emily S Gurley, M Jahangir Hossain, Susan P Montgomery, et al. Etiologies of bacterial meningitis in Bangladesh: results from a hospital-based study. Am J Trop Med Hyg. 2009;81:475–483.
  11. Fish Eleanor N. The X-files in immunity: sex-based differences predispose immune responses. Nature Reviews Immunology. 2008;8(9):737–744.
  12. Julia Fischer, Norma Jung, Nirmal Robinson, et al. Sex differences in immune responses to infectious diseases. Infection. 2015;43(4):399–403.
  13. Kelly S Doran, Marcus Fulde, Nina Gratz, et al. Host–pathogen interactions in bacterial meningitis. Acta neuropathologica. 2016;131(2):185–209.
  14. Anouk M Oordt-Speets, Renee Bolijn, Rosa C van Hoorn, et al. Global etiology of bacterial meningitis: A systematic review and meta-analysis. PloS one. 2018;13(6).
  15. Judith E Mueller , Bradford D Gessner. A hypothetical explanatory model for meningococcal meningitis in the African meningitis belt. Int J Infect Dis. 2009;14:553–559.
  16. Paireau Juliette, Angelica Chen, Helene Broutin, et al. Seasonal dynamics of bacterial meningitis: a time-series analysis. The Lancet global health. 2016;4(6):e370–e377.
  17. Dias SP, Brouwer MC, Bijlsma MW, et al. Sex-based differences in adults with community-acquired bacterial meningitis: a prospective cohort study. Clinical Microbiology and Infection. 2017;23(2):121–e129.
  18. Fischer Julia, Norma Jung, Nirmal Robinson, et al. Sex differences in immune responses to infectious diseases. Infection. 2015;43(4):399–403.
  19. Chaves-Bueno S, Mc Cracken GH. Bacterial meningitis in children. Pediatrc in N Am. 2005;25:795–810.
Creative Commons Attribution License

© . This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and build upon your work non-commercially.