Airborne pollen and fungal spores in Garki, Abuja (North-Central Nigeria)

Aerofloral studies and allergenicity of dominant pollen types in Taraba and Bauchi States of Northeastern Nigeria

Pollen and spores have been identified as major airborne bio-particles inducing respiratory disorders including allergic rhinitis and atopic dermatitis among hypersensitive individuals. The present study was conducted with a view to investigating monthly depositional rate of atmospheric palynomorphs to determine the influence of the immediate vegetation on airborne pollen distribution; allergenic activities of dominant atmospheric pollen types at selected study locations in Taraba and Bauchi States, Northeastern Nigeria. Bioaerosols were collected using Tauber-like pollen traps and subjected to standard palynological treatment procedures, microscopy and photomicrography. Plant enumeration within the surrounding vegetation revealed that some airborne pollen types were produced by local plants at the study locations. Spores of Nephrolepis sp., Pteris sp. and a trilete fern, as well as diatoms were also recovered. Crude protein contents of some dominant pollen types; Borreria verticillata (L.) G.F.W. Meyer and Panicum maximum Jacq. for Taraba State; Leucaena leucocephala (Lam.) de Wit. and Terminalia catappa L. for Bauchi State, were quantified and extracted to sensitize Mus musculus mice for serology (ELISA) and haematology (differential and total white blood cell counts). Statistical significance was tested and recorded in the correlation between levels of serological and haematological parameters elicited by each test group; differences between levels of these parameters elicited by each test group and those of the control, as well as at varying sensitization periods. In the Leucaena leucocephala test group, swollen body and histopathological morbid features showing more extensive areas of inflammatory cells and alveoli filled with fluid in the lungs, were recorded in two dead M. musculus, respectively. The study revealed that all the tested pollen types are possible allergens at the study locations, establishing a complexity of interaction among allergy mediators at varied periods of mice sensitization and forming a paradigm of human immune response to the different pollen allergens.

Microbial Lineages in Sarcoidosis. A Metagenomic Analysis Tailored for Low-Microbial Content Samples

RATIONALE

The etiology of sarcoidosis is unknown, but microbial agents are suspected as triggers.

OBJECTIVES

We sought to identify bacterial, fungal, or viral lineages in specimens from patients with sarcoidosis enriched relative to control subjects using metagenomic DNA sequencing. Because DNA from environmental contamination contributes disproportionately to samples with low authentic microbial content, we developed improved methods for filtering environmental contamination.

METHODS

We analyzed specimens from subjects with sarcoidosis (n = 93), control subjects without sarcoidosis (n = 72), and various environmental controls (n = 150). Sarcoidosis specimens consisted of two independent sets of formalin-fixed, paraffin-embedded lymph node biopsies, BAL, Kveim reagent, and fresh granulomatous spleen from a patient with sarcoidosis. All specimens were analyzed by bacterial 16S and fungal internal transcribed spacer ribosomal RNA gene sequencing. In addition, BAL was analyzed by shotgun sequencing of fractions enriched for viral particles, and Kveim and spleen were subjected to whole-genome shotgun sequencing.

MEASUREMENTS AND MAIN RESULTS

In one tissue set, fungi in the Cladosporiaceae family were enriched in sarcoidosis compared with nonsarcoidosis tissues; in the other tissue set, we detected enrichment of several bacterial lineages in sarcoidosis but not Cladosporiaceae. BAL showed limited enrichment of Aspergillus fungi. Several microbial lineages were detected in Kveim and spleen, including Cladosporium. No microbial lineage was enriched in more than one sample type after correction for multiple comparisons.

CONCLUSIONS

Metagenomic sequencing revealed enrichment of microbes in single types of sarcoidosis samples but limited concordance across sample types. Statistical analysis accounting for environmental contamination was essential to avoiding false positives.

Aeroallergens in North-Central Nigeria

INTRODUCTION AND OBJECTIVES

Aeroallergens are airborne organic substances which are responsible for allergenic diseases in hypersensitive individuals. People are exposed to their allergens either directly or after their entrance into the interiors. The spatio-temporal pattern of aeroallergens and their relationship with weather variability in Abuja and Nassarawa, North-Central Nigeria was studied.

MATERIALS AND METHODS

Aerosamples were trapped with modified Tauber-like pollen traps. Samples were collected monthly and centrifuged at 2500rpm for 5 min and subjected to acetolysis. Meteorological data were collected from the Nigerian Meteorological Agency.

RESULTS AND CONCLUSION

Aeroallergens concentration were unequivocally regulated by weather variables in both locations, indicating the possible use of aeroallergens especially pollen and spores as bio-indicators of weather variations and change. Aeroallergens encountered were fungal spores, pollen, diatom frustules, fern spores, algal cyst/cells in decreasing order of dominance. Among pollen group, Poaceae, Amarathaceae/Chenopodiaceae and Hymenocardia acida dominated. Spores of Smut species, Puccinia, Curvularia and Nigrospora were major contributors among aeromycoflora. Fungal spores morphotype dominated during the rainier months and were major contributors of the aeroallergen spectrum with those belonging to Deuteromycete preponderant. Aeroallergens which were previously identified as triggers of conjunctivitis, asthma, allergic sinusitis and bronchopulmonary allergic diseases were frequently present in both locations. Pollen prevailed more during the harmattan, influenced by northeast trade wind. Pollen component differed and was based on autochthonous source plants, indicating difference in sub-vegetational types.

Comparative study of aeropollen and pollinosis cases

Research linking pollen grains in the air with allergy cases (pollinosis) is still incipient in Africa. To close this gap, aerosamplers were placed in Gbagada, Lagos State and harvested monthly from January 2013 to December 2014. Data obtained was correlated with allergy cases (wheezing cough, rhinitis, and allergic conjunctivitis) from Gbagada General Hospital Lagos. Dominant pollen grains recovered were those of Alchornea cordifolia, Amaranthaceae, Casuarina equisetifolia, Cyperaceae, and Poaceae. Pollinosis data revealed that wheezing cough had the highest records in 2013 (1153) and 2014 (1409) while individuals of the age group 15-49 years had the highest number of pollinosis cases for both years. Peak pollen season in 2013 was from October-December; similarly, October, November, and December recorded the highest incidence of wheezing cough (225), rhinitis (21), and allergic conjunctivitis (56) respectively. In 2014, peak pollen season was from October-March while October recorded the highest number of cases of allergic conjunctivitis and rhinitis (81 and 32 respectively) and wheezing cough cases were highest in November (299). Total pollen count had positive significant correlation (p ≤ 0.05) with wheezing cough cases for both years. Individually, each dominant pollen had positive significant correlation (p ≤ 0.05) with wheezing cough cases in 2013 while only Cyperaceae and Poaceae pollen had positive significant correlation (p ≤ 0.05) with wheezing cough in 2014. Continuous collection of aeropollen and pollinosis data from more locations within Nigeria is recommended to provide an appropriate epidemiology of pollinosis cases in the country and ascertain possible responsible pollen grains.