Incidence of invasive Haemophilus influenzae type b infections in Filipino children

MRI Spectrum of Haemophilus influenzae Meningoencephalitis in Children

Background and Purpose:

Haemophilus influenzae type b (Hib) infection occurs mostly in children and is transmitted from person to person through the respiratory pathway. Hib strain is associated with meningitis or encephalitis. It is not an uncommon infection, particularly, in the developing world. This prospective cohort study was done with the aim of describing imaging findings in patients with Hib meningoencephalitis.

Materials and Methods:

In a prospective cohort study, consecutive children admitted in the pediatric emergency unit with acute febrile encephalopathy were enrolled. The clinical details, CSF analysis, and microbiological and serological investigations were recorded on a case record proforma. Children with confirmed Hib meningoencephalitis were included in this study. Clinicoradiological features were assessed.

Results:

A total of 16 patients with acute febrile encephalopathy, in whom CSF latex agglutination, CSF culture, or CSF multiplex PCR were positive for H. influenzae were included in this study. All these children were investigated with magnetic resonance imaging (MRI) brain. Important imaging findings were meningitis, predominantly around frontoparietal lobes (43%), cerebritis (28%), ventriculitis (14%), and subdural collections (21.5%). One patient had features consistent with acute disseminated encephalomyelitis (ADEM) while four patients had normal MRI scan.

Conclusions:

H. influenzae is still a common cause of meningitis in infants and children in the developing world. We have tried to study the most common MRI features associated with Hib infection to help radiologists alert the treating clinicians to further investigate these patients for appropriate prognostication.

A systematic review and critical evaluation of invasive Haemophilus influenzae type B disease burden studies in Asia from the last decade: lessons learned for invasive bacterial disease surveillance

In Asia, questions regarding the burden of Haemophilus influenzae type b (Hib) disease have delayed decision-making on introduction of Hib vaccine. However, over the past decade many studies have been published regarding Hib disease burden in Asia. We conducted a systematic literature review of all reports of Hib disease burden in Asia between 1998 and 2009, and critically reviewed their methods and data quality. We identified 94 studies from 28 countries in Asia presenting data on Hib disease burden. Of the 94 studies reviewed, 49 (52%) used a case definition consistent with World Health Organization standards, and 47 (50%) described laboratory methodology used. Twenty-seven surveillance studies presented data on incidence of Hib disease, with 8 (30%) accounting for missed cases, 6 (15%) accounting for cases with missed diagnostic tests, and 2 (7%) that considered prior antibiotic use. Of the 21 studies that provided incidence data for Hib meningitis, 10 (48%) used active, prospective, population-based surveillance, and found unadjusted incidence rates of Hib meningitis ranging from a low of 0.98 per 100,000 child-years in children aged less than 5 years in China to a high of 28 per 100,000 child-years in children less than 5 years in Mongolia. Of 49 studies that reported the etiology of bacterial meningitis, 30 (60%) identified Hib as the most common cause. This review highlights the importance of using rigorous methodologies, including standardized surveillance methods and appropriate laboratory diagnostic tests, when conducting studies measuring the burden of invasive bacterial diseases including those caused by Hib. When poorly conducted, studies can underestimate disease burden and lead to inappropriate decisions about vaccine introduction.

Clinical case review: a method to improve identification of true clinical and radiographic pneumonia in children meeting the World Health Organization definition for pneumonia

Background

The World Health Organization's (WHO) case definition for childhood pneumonia, composed of simple clinical signs of cough, difficult breathing and fast breathing, is widely used in resource poor settings to guide management of acute respiratory infections. The definition is also commonly used as an entry criteria or endpoint in different intervention and disease burden studies.

Methods

A group of paediatricians conducted a retrospective review of clinical and laboratory data including C-reactive protein concentration and chest radiograph findings among Filipino children hospitalised in the Bohol Regional Hospital who were enrolled in a pneumococcal vaccine efficacy study and had an episode of respiratory disease fulfilling the WHO case definition for clinical pneumonia. Our aim was to evaluate which disease entities the WHO definition actually captures and what is the probable aetiology of respiratory infections among these episodes diagnosed in this population.

Results

Among the 12,194 children enrolled to the vaccine study we recorded 1,195 disease episodes leading to hospitalisation which fulfilled the WHO criteria for pneumonia. In total, 34% of these episodes showed radiographic evidence of pneumonia and 11% were classified as definitive or probable bacterial pneumonia. Over 95% of episodes of WHO-defined severe pneumonia (with chest indrawing) had an acute lower respiratory infection as final diagnosis whereas 34% of those with non-severe clinical pneumonia had gastroenteritis or other non-respiratory infection as main cause of hospitalisation.

Conclusion

The WHO definition for severe pneumonia shows high specificity for acute lower respiratory infection and provides a tool to compare the total burden of lower respiratory infections in different settings.

Trial registration

ISRCTN62323832

Serious community-acquired paediatric infections in rural Asia (Bohol Island, Philippines): bacterial meningitis in children less than 5 years of age

This paper describes the clinical profile and aetiology of bacterial meningitis in infants and children less than 5 y old admitted to a rural general hospital in the Philippines. A total of 989 infants and children 0-59 months old with suspected meningitis using a standardized guideline based on clinical signs and symptoms were prospectively enrolled from April 1994 to May 2000. Blood and CSF were drawn on admission for culture, antigen testing and cell count. All had blood cultures and 623 (63%) had CSF samples. Bacterial aetiology was found in 54 (5%). The most common bacterial pathogens were H. influenzae type b (Hib) (20, 37%) and S. pneumoniae (Pnc) (10, 18%). All of the Hib infections and 8 (80%) Pnc infections were in infants less than 1 y old. 12 (22%) of the subjects with bacterial meningitis died. All strains of S. pneumoniae and H. influenzae were sensitive to chloramphenicol, cotrimoxazole and ampicillin. In conclusion, S. pneumoniae and H. influenzae type b are the most common aetiological agents of bacterial meningitis in a rural area in the Philippines, and occur especially in infants less than 1 y old. Aetiological agents were susceptible to the currently recommended antimicrobial agents.