First record of nasopharyngeal myiasis caused by Cephalopina titillator (Clark, 1816) in camel (Camelus dromedarius Linnaeus, 1758) in Uzbekistan.

Nasopharyngeal myiasis caused by the camel nasal bot, Cephalopina titillator, is very common in old world camelids and is usually found at necropsy or during meat inspection. Herein we report massive infection with C. titillator in a 9 years old female one-humped camel slaughtered on February 18, 2024 in the village of Kizil Uy, Nukus District, Republic of Karakalpakstan, northwestern Uzbekistan. A total of 69 larvae: 20 first stage larva (28.9%), 31  second stage larva (44.9%), and 18 third stage larva (26.0%) were detected in the nasal passages and pharynx of the camel. Morphological and morphometrical characters of all larval stages are illustrated and detailed in this article. To our knowledge this is the first record of camel nasal bot infestation in Uzbekistan. Future epidemiological studies are needed to shed light on the prevalence, seasonal fluctuation, clinical impact and economic burden of nasopharyngeal myiasis in dromedary camels of the country.

Nasopharyngeal colonization with pathobionts is associated with susceptibility to respiratory illnesses in young children.

Some children are more susceptible to viral and bacterial respiratory infections in the first few years of life than others. However, the factors contributing to this susceptibility are incompletely understood. In a retrospective analysis of clinical samples collected from a prospectively-enrolled cohort of 358 children we sought associations between physician-attended illness visits and bacterial colonization in the first five years of life. A subset of children was identified by unsupervised clustering analysis as infection and allergy prone (IAP). Several respiratory infection- and allergy-mediated illnesses co-occurred at higher rates in IAP children, while the rates of other illnesses were not significantly different between the groups. Analyses of nasopharyngeal (NP) pathobionts and microbiota commensals showed that early age of first colonization with pathobionts Streptococcus pneumonia, non-typeable Haemophilus influenzae, and Moraxella catarrhalis was associated with IAP children, and particularly Moraxella abundance was negatively associated with NP microbiome diversity. We conclude that mucosal pathobiont exposures in early life can influence susceptibility to respiratory illnesses in children.

Nasopharyngeal Pneumococcal Carriage in Nigeria: a two-site, population-based survey.

Changes in nasopharyngeal (NP) carriage of vaccine-type (VT) Streptococcus pneumoniae can be used to assess the effectiveness of a pneumococcal conjugate vaccine (PCV10). We conducted a baseline carriage survey in rural (Kumbotso, Kano) and urban (Pakoto, Ogun) Nigeria. In this cross-sectional study, we obtained data on demography, clinical history, risk factors, and took NP swabs for pneumococcal culture. We calculated crude and age-standardised carriage prevalence and used log-binomial regression to assess risk factors for carriage. Among children aged <5 years, 92% (95% CI: 88-95%) and 78% (73-82%), respectively, carried any pneumococcus and 48% and 50%, respectively, carried PCV10 serotypes. In Kumbotso, carriage prevalence was >40% across all ages. The age-standardized prevalence of pneumococcal carriage was 66% in Kumbotso and 40% in Pakoto. The most commonly identified serotypes were 19 F, 6 A and 23 F. Risk factors for carriage were young age, recent rhinorrhoea, cohabitation with ≥2 children aged <5 years, and sharing a bed with ≥2 persons. Pneumococcal carriage prevalence is high in this Nigerian population. Persisting prevalence of VT-carriage in older children and adults suggests that PCV10 introduction in children will not eliminate transmission of vaccine serotypes rapidly. High vaccine coverage will therefore be required to ensure full protection of children.

Enhanced nasopharyngeal infection and shedding associated with an epidemic lineage of emm3 group A Streptococcus.

BACKGROUND: A group A Streptococcus (GAS) lineage of genotype emm3, sequence type 15 (ST15) was associated with a 6 month upsurge in invasive GAS disease in the UK. The epidemic lineage (Lineage C) had lost 2 typical emm3 prophages, Φ315.1 and Φ315.2 associated with the superantigen ssa, but gained a different prophage (ΦUK-M3.1) associated with a different superantigen, speC and a DNAse spd1. METHODS AND RESULTS: The presence of speC and spd1 in Lineage C ST15 strains enhanced both in vitro mitogenic and DNase activities over non-Lineage C ST15 strains. Invasive disease models in Galleria mellonella and SPEC-sensitive transgenic mice, revealed no difference in overall invasiveness of Lineage C ST15 strains compared with non-Lineage C ST15 strains, consistent with clinical and epidemiological analysis. Lineage C strains did however markedly prolong murine nasal infection with enhanced nasal and airborne shedding compared with non-Lineage C strains. Deletion of speC or spd1 in 2 Lineage C strains identified a possible role for spd1 in airborne shedding from the murine nasopharynx. CONCLUSIONS: Nasopharyngeal infection and shedding of Lineage C strains was enhanced compared with non-Lineage C strains and this was, in part, mediated by the gain of the DNase spd1 through prophage acquisition.

Corynebacterium species nasopharyngeal carriage in asymptomatic individuals aged ≥ 65 years in Germany.

PURPOSE: The prevalence of protective anti-diphtheria toxin antibodies decreases with age. Therefore, the elderly might serve as reservoir for potentially toxigenic Corynebacterium (C.) species (C. diphtheriae, C. ulcerans, and C. pseudotuberculosis). This study aimed to examine the colonization rate of the nasopharynx with corynebacteria of individuals aged 65 years and older. METHODS: In the period from October 2012 to June 2013, nasal and throat swabs were taken from 714 asymptomatic subjects aged 65-106 years (average age 77.2) at three regions in Germany and investigated for Corynebacterium species. RESULTS: A total of 402 strains of Corynebacterium species were isolated from 388 out of 714 asymptomatic subjects (carriage rate 54.3%). The carriage rate was significantly higher in study participants living in retirement homes (68.4%) compared to those living autonomously at home (51.1%). Strains were isolated mostly from the nose (99%). Corynebacterium accolens was the most often isolated species (39.8%), followed by C. propinquum (24.1%), C. pseudodiphtheriticum (19.4%), and C. tuberculostearicum (10.2%). No C. diphtheriae, C. ulcerans, and C. pseudotuberculosis strains were isolated. A subsample of 74 subjects was tested serologically for anti-diphtheria antibodies. Protective anti-diphtheria toxin antibodies were found in 29.7% of the subjects; 70.3% showed no protective immunity. CONCLUSIONS: These results suggest that carriage of potentially toxigenic corynebacteria is very rare among people aged 65 and older in Germany. However, the low prevalence of protective anti-diphtheria toxin antibodies might pose a risk for acquiring diphtheria especially for the elderly.

An objective assessment of halitosis in children with adenoid vegetation during pre- and post-operative period.

OBJECTIVES: Although most specialists in otorhinolaryngology and pediatrics find halitosis to be a common problem in children with adenoid hypertrophy, there are no objective data on this topic in the literature. Whether adenoid hypertrophy is a risk factor for halitosis or whether halitosis is a sign of adenoid hypertrophy remains unclear. Thus, the aim of this study was to investigate whether children diagnosed with adenoid hypertrophy have a higher probability of halitosis than do children in the normal population and whether adenoidectomy can decrease oral malodor. METHODS: Forty children with adenoid hypertrophy and 40 healthy subjects aged 5-15 years were included in the study. The children with adenoid hypertrophy underwent adenoidectomy operations and were followed for 3 months. We measured volatile sulfur compounds (VSCs), hydrogen sulfide (H2S), methyl mercaptan (CH3SH), and dimethyl sulfide (CH3)2S using an objective method, a portable gas chromatograph (OralChroma; AbiMedical, Osaka, Japan). RESULTS: The mean CH3SH and (CH3)2S levels were significantly different (p < 0.05) between the adenoid hypertrophy group and the controls. The H2S, CH3SH, and (CH3)2S levels in the third postoperative month were significantly lower (p < 0.05) than those in the preoperative period, and there was no significant difference postoperatively between the patients with adenoid hypertrophy and controls. There was a positive correlation between age and VSC levels, and CH3SH levels were significantly higher in patients with ventilation tube insertion, rather than just adenoidectomy. CONCLUSIONS: There was a statistically significant association between halitosis and adenoid hypertrophy, and a significant improvement in halitosis was obtained following adenoidectomy. The present study provides an association between halitosis and adenoid hypertrophy. If there is no other oral pathology causing halitosis, halitosis can be a sign of adenoid hypertrophy in children.

Endoscopic bilateral congenital choanal atresia repair of 112 cases, evolving concept and technical experience.

OBJECTIVE: This study aims to present 18 years' experience with endoscopic treatment of bilateral congenital choanal atresia as regard to management concept, surgical technique, results, pitfalls, and complications. PATIENTS AND METHODS: A retrospective study including 112 cases of bilateral congenital choanal atresia, treated at Mansoura University Hospital endoscopically in the period from January 1998 to March 2015. As far as we know, this is the largest study group on transnasal endoscopic choanal atresia repair in literature. RESULTS: One hundred and twelve infants (87 females, 25 males) were included in the study. Age at operation ranged between 1 day and 28 days (8.75 days in average), and body weight average was 2.76kg. All patients were diagnosed at birth except 3 infants. In this study, 85 cases were mixed atresia, 25 cases were bony atresia, and only two cases were membranous. In all cases, obliterated choana bone and vomer bone was removed, lateral wall drilling was used in 33 cases. Follow up ranged between 6 months and 18 years (95.6 months in average). The most common complication was restenosis, occurred in 42% (47 cases). Second-look procedure was done in 68 cases. The need for second-look evaluation with stent group was 74.5% (62 out of 83 infants), whereas in non-stent group was 20.6% (6 out of 29 infants). CONCLUSION: Endoscopic repair of bilateral choanal atresia is a safe, effective technique with minimal complication. Usage of 30 degree sinuscope permits better visualization and higher accessibility for the surgical instruments. Surgically formed wide single neochoana with removal of all intervening tissue surroundings, and good follow up permit higher success rate without stenting. Advanced learning curve permits tailoring the perfect surgery with minimal tissue injury and better outcome. Post-operative choanal dilatation using esophageal dilators under endoscopic examination decrease the need for stenting and second-look evaluation.

Tumors and tumor-like conditions of the nasal cavity, paranasal sinuses, and nasopharynx: A study of 206 cases.

INTRODUCTION: The nasal cavity, paranasal sinuses, and nasopharynx though in continuity form a complex system of upper respiratory tract; this region is endowed with a variety of elements such as epithelial, glandular, lymphoid, cartilage, and bone and is also exposed to a variety of infections, tumor-like and true neoplastic conditions. AIMS AND OBJECTIVES: To find out the frequency of various tumors and tumor-like conditions of the nasal cavity, paranasal sinuses, and nasopharynx. MATERIALS AND METHODS: The present study is an analysis of 206 tumors and tumor-like conditions of the nasal cavity, paranasal sinuses, and nasopharynx diagnosed during a period of 5 years. RESULTS: The patients' age ranged from 14 months to 85 years. Benign lesions were predominant in the second and third decades, with 30 cases (68.1%) occurring in that age group. Malignancies occurred predominantly in the sixth and seventh decades with 28 (60.9%) cases in this age group. Benign lesions in the nasopharynx comprised 75% cases and malignancies 25%. Eighty-three (71.5%) tumor-like conditions occurred in the nose and antrochoanal region. CONCLUSION: Angiofibroma was the most common benign tumor accounting for 25.55% of all neoplastic lesions. Squamous cell carcinoma was the most common malignancy at this site constituting 50% of all malignancies.

Encephalitis-Associated Human Metapneumovirus Pneumonia in Adult, Australia.

Human metapneumovirus pneumonia, most commonly found in children, was diagnosed in an adult with encephalitis. This case suggests that testing for human metapneumovirus RNA in nasopharyngeal aspirate and cerebrospinal fluid samples should be considered in adults with encephalitis who have a preceding respiratory infection.

Prevalence of ear disease in dogs undergoing multidetector thin-slice computed tomography of the head.

Previous reports describing the prevalence of ear diseases in dogs have primarily been based on dogs presenting with clinical signs of disease. The prevalence of subclinical ear disease remains unknown. The purpose of this cross-sectional retrospective study was to describe the prevalence of lesions consistent with middle and external ear disease in dogs presented for multidetector computed tomography (CT) of the head and/or cranial cervical spine at our hospital during the period of July 2011 and August 2013. For each included dog, data recorded were signalment, CT findings, diagnosis, and treatment. A total of 199 dogs met inclusion criteria. Nineteen dogs (9.5%) were referred for evaluation of suspected ear disease and 27 dogs (13.5%) had histories or physical examination findings consistent with otitis externa. A total of 163 dogs (81.9%) had CT lesions consistent with external ear disease (i.e. ear canal mineralization, external canal thickening, and/or narrowing of the external canal). Thirty-nine dogs (19.5%) had CT lesions consistent with middle ear disease (i.e. soft tissue attenuating/fluid material in the tympanic bullae, bulla wall thickening or lysis, and/or periosteal proliferation of the temporal bone). Findings from this study indicated that the prevalence of external and middle ear disease in dogs could be higher than that previously reported.

Nasopharyngeal carriage, antibiogram & serotype distribution of Streptococcus pneumoniae among healthy under five children.

BACKGROUND & OBJECTIVES: Information related to nasopharyngeal carriage of Streptococcus pneumoniae among healthy children is scanty in India. This prospective study was undertaken to determine the presence of asymptomatic nasopharyngeal colonization, assess serogroups/types (SGT) and drug resistance of S. pneumoniae in children below five years of age. METHODS: A total of 109 male and 81 female children in the age group of three months to five years belonging to different socio-economic classes were enrolled. They were recruited across all age groups from those attending paediatric OPD of a tertiary care and research centre for immunization program. Fifty three isolates identified as pneumococci were tested for their antimicrobial susceptibility pattern by Kirby-Bauer's disc diffusion and E-Test methods. Serotyping was performed by detection of the quelling reaction with specific antiserum. RESULT: The pneumococcal carriage rate in the study population was 27.9 per cent. The isolation rate was associated with age being higher (49.2%) in smaller children (3-12 months) and among male (62.2%). The most prevalent SGTs were 19 followed by 10, 14 and 7; 21 per cent of isolates belonging to serotype 10 (n=7) were 11 (n=4) were not covered in any of the conjugate vaccines currently available in Indian market. Resistance to co-trimoxazole, tetracycline, penicillin and erythromycin was observed in 91 per cent (n=48), 36 per cent (n=19), 17 per cent (n=9) and 9 per cent (n=5) isolates, respectively. All the penicillin resistant isolates were found to be intermediately resistant by E-Test. Multidrug resistance was observed in 19 per cent (n=10) isolates. INTERPRETATION & CONCLUSIONS: High level of antibiotic resistance was present in S. pneumoniae isolated from healthy children below age five. A pneumococcal conjugate vaccine with the prevailing SGTs would help to reduce the pool of antibiotic resistant pneumococci. Continued surveillance of serotypes and tracking susceptibility pattern of S. pneumoniae will help to introduce appropriate vaccination protocols.

Nasopharyngeal cystic lesions: Tornwaldt and mucous retention cysts of the nasopharynx: findings on MR imaging.

OBJECTIVE: Nasopharyngeal cystic lesions are commonly encountered on magnetic resonance imaging with significantly overlapped imaging characteristics. The purpose of this study was to determine the prevalence and distinguishing imaging features of cystic lesions in the nasopharynx in the largest patient series to date. METHODS: After institutional review board approval, consecutive head magnetic resonance images of 3000 patients performed at 1.5 T between June 2010 and April 2011 were retrospectively reviewed for cystic nasopharyngeal lesions. Location, size, and signal characteristic of cystic lesions were recorded. Electronic medical records were reviewed for patient demographics, symptoms, and underlying conditions. RESULTS: Among 3000 patients, 6% had Tornwaldt cysts (peak prevalence, 51-60 years old) and 10% had mucous retention cysts (peak prevalence, 41-50 years old). A significant correlation between human immunodeficiency virus infection and mucous retention cysts was observed (P < 0.001). CONCLUSIONS: The prevalence of Tornwaldt cysts was slightly higher than previously described in the literature. Additionally, younger and older patients had the lowest prevalence of Tornwaldt cyst, suggesting these lesions are acquired and subsequently involute with time. A significant correlation was observed between human immunodeficiency virus infection and mucous retention cysts.

Effect of the 13-valent pneumococcal conjugate vaccine on nasopharyngeal colonization by Streptococcus pneumoniae--Alaska, 2008-2012.

BACKGROUND: In 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) replaced a 7-valent vaccine (PCV7) that contained all PCV7 serotypes plus 6 additional serotypes (PCV6+). We conducted annual surveys from 2008 to 2012 to determine the effect of PCV13 on colonization by pneumococcal serotypes. METHODS: We obtained nasopharyngeal swabs for pneumococcal identification and serotyping from residents of all ages at 8 rural villages and children age <60 months at 2 urban clinics. We conducted interviews/medical records review for all participants. RESULTS: A total of 18 207 nasopharyngeal swabs (rural = 16 098; urban = 2109) were collected. From 2008 to 2012, 84% of rural and 90% of urban children age <5 years were age-appropriately vaccinated with a PCV. Overall pneumococcal colonization prevalence remained stable among rural (66%) and urban (35%) children age <5 years, and adults age ≥18 years (14%). Colonization by PCV6+ serotypes declined significantly among rural children age <5 years, urban children age <5, and adults age ≥18 over the course of the study (25%-5%, 22%-9%, 22%-6%, respectively). CONCLUSIONS: PCV13 was rapidly introduced into the Alaska childhood immunization schedule and reduced colonization by PCV6+ serotypes among children. Unvaccinated adults also experienced comparable reductions in vaccine serotype colonization indicating substantial indirect protection from PCV13.

[The prevalence of different Streptococcus pneumoniaе serotypes in the children presenting with ENT infections or carrying nasopharyngeal pathogens].

The objective of the present study was to elucidate the etiopathological significance of various Streptococcus pneumoniae serotypes in the children presenting with ENT infections and carrying nasopharyngeal pathogens. The incidence of the latter condition was 19.5% in the children free from S. pneumoniae infection in comparison with 20.9% and 30.7% in those having diagnosis of otitis media and rhinosinusitis respectively. Fifty five (88.8%) of the 62 isolated streptococcal strains were grouped into types with the use of multiplex PCR. Twelve serotypes were identified in the patients presenting with rhinosinusitis with the predominance of 6A/6B and 3 (40.5%) compared with seven isolated from the carriers of nasopharyngeal pathogens. In this group, type 3 also prevailed (26.5%) whereas other serotypes occurred less frequently: 23F (13,4%), indivisible totality of 8, 9V, 9A, 1F, 11A, 211B, 11C, 11D, 12F, 15A, and 33F (13.4%), 20 (6.7%), 19A (6.7%), 14 (6.7%), 6A,6B (6.7%). The serotypes of S. pneumoniae isolated from the patients with rhinosinusitis were found to show 55.3% identity with those present in the composition of the conjugated 7-valent pneumococcal vaccines, 63.2% identity with the 10-valent vaccine, 81.6% identity with the 11p-valnet vaccine, and 84.2% identity with the 13-valent vaccine.

A study of the role of different forms of chronic rhinitis in the development of otitis media with effusion in children affected by adenoid hypertrophy.

OBJECTIVE: The aim of the present study was to evaluate the role of the different forms of chronic rhinitis in the pathogenesis of otitis media with effusion in children affected by obstructive adenoid hypertrophy. METHODS: 81 patients, aged between 4 and 15 years (mean age of 6.9 years), affected by obstructive adenoid hypertrophy were evaluated. All patients underwent accurate history taking, physical examination with endoscopy of the nasopharynx, skin prick test, nasal cytology and hearing evaluation. RESULTS: Nasal citology showed that 21% of patients had a non-allergic rhinitis (NAR) subtype, 17.4% NAR overlapping with infectious rhinitis (IR), 29.6% IR, 4.9% allergic rhinitis (AR), 2.5% AR overlapping with IR and the remaining 24.6% a negative cytology. The presence of OME was positively correlated with neutrophils (p = 0.01) and mast cells (p = 0.022), while it was negatively correlated with the presence of eosinophils (p = 0.02) and bacteria (p = 0.02). CONCLUSIONS: A chronic rhinitis was present in more than 70% of children with AH and 60% of them showed OME. Nasal cytology together with SPT showed that AR was rarely present in this group of children, while the mast-cells and neutrophils positively correlated with OME.

An interdisciplinary study of orthodontic, orthopedic, and otorhinolaryngological findings in 12-14-year-old preorthodontic children.

BACKGROUND AND OBJECTIVE: Malocclusion, the body posture, and the breathing pattern may correlate, but this issue is still controversial. The aim of the study was to examine the relationship between the type of malocclusion, the body posture, and the nasopharyngeal obstruction in 12-14-year-old children. MATERIAL AND METHODS: The study group consisted of 76 orthodontic patients (35 boys, 41 girls) aged 12-14 years (mean age, 12.79 years [SD, 0.98]). All the patients were examined by the same orthodontist (study model and cephalometric radiograph analysis), the same orthopedic surgeon (body posture examined from the front, the side, and the back), and the same otorhinolaryngologist (anterior and posterior rhinoscopy and pharyngoscopy) in a blind manner. RESULTS: The prevalence of a poor body posture and a nasopharyngeal pathology was high in the present study. In total, 48.7% of the orthodontic patients had a kyphotic posture and 55.3% a rib hump in the thoracic region. The nasopharyngeal pathology was diagnosed in 78.9% of the patients. The patients with the kyphotic posture had a higher mandibular plane angle (MP-SN) and a lower sagittal position of the mandible SNB angle. A deeper overbite correlated with shoulder and scapular asymmetry. The kyphotic posture was diagnosed in 55.0% of the patients with the nasopharyngeal pathology. CONCLUSIONS: The sagittal body posture was related to the vertical craniofacial parameters and hypertrophy of the tonsils and/or the adenoids. The study showed no relationship between the degree of crowding, the presence of a posterior cross bite, orthopedic parameters, and a breathing pattern.

The association between sleep apnea and young adults with hypertension.

OBJECTIVES/HYPOTHESIS: To study the association between sleep apnea and hypertension in a younger age group than previously studied, adding upper airway sizes at endoscopy as important compounding variables not often included in the past. STUDY DESIGN: Case control. METHODS: We analyzed data on sleep-disordered breathing (based on polysomnography tests), body mass index (BMI), neck circumference, upper airway endoscopy sizes, and habitus and health history in 120 hypertensive and 120 nonhypertensive participants in a clinic-based setting. Independent t test, χ(2) , multivariate analysis, and binary logistic regression models were used for case-control comparison. RESULTS: The mean age of the participants was 27 years; 67.5% were male. The incidence and severity of sleep apnea were significantly higher in the hypertensive than the control subjects. Persons with hypertension had an OR of 2.7 times of having comorbid sleep apnea than patients without hypertension (95% confidence interval [CI] 1.2-6.1). Persons with sleep apnea (AHI [apnea-hypopnea index] ≥ 5) had an OR of 2.76 (95% CI 1.57-4.86), and persons with severe sleep apnea (AHI ≥ 30) had an OR 7.94 (95% CI 4.21-15.33) for having hypertension than did persons without sleep apnea. Although adjustments for the compounding factors, particularly BMI, decreased the OR to a large degree, subjects with severe sleep apnea were still 72% more likely to have hypertension than subjects without sleep apnea. CONCLUSIONS: Sleep apnea is related to hypertension in young adults aged 18 to 40 years. The association was more pronounced with the increasing severity of sleep apnea. Screening for sleep apnea should be considered in young adults with hypertension.

Rhinosporidiosis in southwest Bengal.

Rhinosporidiosis is a non-contagious chronic granulomatous disease that is prevalent in southern India and Sri Lanka. It has been known for centuries, but the details of the disease and the precise manner of its transmission have, until recently, remained unknown. Our institution sees many cases of this disease and we investigate the management protocol and its recent advances and include a review of the published literature. A total of 152 patients who were treated at Bankura Sammilani Medical College were studied between 2005 and 2011. The most common age group affected were those aged between 11 and 20 years of age and the male-to-female ratio was 1.9:1. Three patients suffered recurrent disease - one experienced it on the same site and the others on distant sites. Eleven patients with inadequate excision in which the margins were not free from disease were treated with dapsone therapy without any reported recurrence. It is a common disease in southwestern West Bengal. Surgical excision with electrocoagulation of the base is the main treatment, and dapsone therapy is recommended in order to prevent recurrences in multiple sites of affection and inadequate surgically excised cases. Although the disease occurs sporadically in most parts of the world, we see many patients in our area.

Rates of acquisition and clearance of pneumococcal serotypes in the nasopharynges of children in Kilifi District, Kenya.

BACKGROUND: To understand and model the impact of pneumococcal conjugate vaccines at the population level, we need to know the transmission dynamics of individual pneumococcal serotypes. We estimated serotype-specific clearance and acquisition rates of nasopharyngeal colonization among Kenyan children. METHODS: Children aged 3-59 months who were identified as carriers in a cross-sectional survey were followed-up approximately 1, 2, 4, 8, 16, and 32 days later and monthly thereafter until culture of 2 consecutive swabs yielded an alternative serotype or no pneumococcus. Serotype-specific clearance rates were estimated by exponential regression of interval-censored carriage durations. Duration was estimated as the reciprocal of the clearance rate, and acquisition rates were estimated on the basis of prevalence and duration, assuming an equilibrium state. RESULTS: Of 2840 children sampled between October 2006 and December 2008, 1868 were carriers. The clearance rate was 0.032 episodes/day (95% confidence interval [CI], .030-.034), for a carriage duration of 31.3 days, and the rate varied by serotype (P< .0005). Carriage durations for the 28 serotypes with ≥ 10 carriers ranged from 6.7 to 50 days. Clearance rates increased with year of age, adjusted for serotype (hazard ratio, 1.21; 95% CI, 1.15-1.27). The acquisition rate was 0.061 episodes/day (95% CI, .055-.067), which did not vary with age. Serotype-specific acquisition rates varied from 0.0002 to 0.0022 episodes/day. Serotype-specific acquisition rates correlated with prevalence (r=0.91; P< .00005) and with acquisition rates measured in a separate study involving 1404 newborns in Kilifi (r=0.87; P< .00005). CONCLUSIONS: The large sample size and short swabbing intervals provide a precise description of the prevalence, duration, and acquisition of carriage of 28 pneumococcal serotypes. In Kilifi, young children experience approximately 8 episodes of carriage per year. The declining prevalence with age is attributable to increasing clearance rates.