Weekly Report

5 November 2021

City
Overall Risk
Tree Pollen
Grass Pollen
Weed Pollen
Mould Spores

Summary

The rain that has fallen over many parts of South Africa recently has reduced pollen counts and spurred mould growth. Moulds often increase in spring and autumn especially after rain, as they thrive in warm, wet weather. High mould levels were seen in Durban, with lower counts in the rest of the country. Spikes for the allergenic mould Cladosporium were seen in Kimberley and Pretoria, while high allergenic Alternaria concentrations were detected in Cape Town. The grass count was moderate in the winter rainfall city of Cape Town, but low at the summer rainfall sites.

Cape Town

Moderate grass levels with low tree and weed levels were seen during this sampling period. Tree pollen included bushwillow (Combretaceae), cypress (Cupressaceae), gum (Myrtaceae), mulberry (Moraceae), olive (Oleaceae), pine (Pinaceae), plane (Platanus sp.) and poplar (Populus sp.). The weed pollen detected were the daisy family (Asteraceae), the cabbage family (Brassicaceae), erica (Ericaceae), sedges (Cyperaceae), protea (Proteaceae), spurges (Euphorbiaceae), English plantain, sorrel (Rumex sp.), the citrus family (Rutaceae), the mezereum family (Thymelaeaceae) and nettles (Urticaceae). Overall mould counts were low, but a spike in the allergenic fungal spore Alternaria was seen.

Johannesburg

Low levels of grasses, weeds, trees and moulds were detected during this sampling period. Tree pollen included pecan (Carya sp.), bushwillow (Combretaceae), mulberry (Moraceae), yellowwood (Podocarpaceae), mesquite (Prosopis sp.) and oak (Quercus sp.). The only weed pollen detected was from the protea family (Proteaceae).

Pretoria

Pollen was reduced by rain, but mould counts increased. Grasses and weeds remained low during this sampling period, with tree pollen also decreasing to low levels. Flowering trees included cypress (Cupressaceae), pecan (Carya sp.), bushwillow (Combretaceae), mulberry (Moraceae), mesquite (Prosopis sp.), pine (Pinaceae) and yellowwood (Podocarpaceae). Weeds included sorrel (Rumex sp.), the carnation family (Caryophyllaceae) and English plantain (Plantaginaceae). Moulds were generally low but spikes for the allergenic spore Cladosporium are noted.

Bloemfontein

A power failure at the site meant that data could not be collected for this week. The results from the previous sampling period are repeated: Grass, weed and tree pollen counts were low. Tree pollen included acacia (Acacia sp.), bushwillow (Combretaceae), waxberry (Morella sp.), gum (Myrtaceae), mulberry (Moraceae), plane (Platanus sp.) and karee (Rhus sp. / Searsia sp.). The weed pollen detected were the daisy family (Asteraceae), goosefoot (Chenopodiaceae) and pigmyweeds (Crassula sp.). Mould levels were low. Charcoal particles from the recent fires around Bloemfontein were still observed.

Kimberley

Very low pollen counts were detected during this sampling period. Tree pollen included the sumac family (Anacardiaceae), hackberry (Celtis sp.), bushwillow (Combretaceae), the pea family (Fabaceae), cypress (Cupressaceae), gum (Myrtaceae), olive (Oleaceae) and yellowwood (Podocarpaceae). Weed pollen was from the aloe family (Asphodelaceae), the carnation family (Caryophyllaceae), goosefoot (Chenopodiaceae), sorrel (Rumex sp.), knotweeds (Polygonaceae) and English plantain. Mould counts were low, but a spike in the allergenic fungal spore Cladosporium was seen.

Durban

Grasses, trees and weeds were low. Flowering trees included the monkey puzzle tree (Araucaria angustifolia), pecan (Carya sp.), mulberry (Moraceae), pine (Pinaceae), yellowwood (Podocarpaceae), acacia (Acacia sp.), gum (Myrtaceae), hackberry (Celtis sp.) and poplar (Populaceae). Weeds detected were nettle (Urticaceae), sorrel (Rumex sp.), English plantain (Plantaginaceae), protea (Proteaceae), sedges (Cyperaceae) and spurges (Euphorbia sp.). Moulds were high as ascospores surged after rain and spikes were noted for the allergenic spore Cladosporium.

Gqeberha

Pollen levels were low in all categories. Tree pollen detected included the monkey puzzle tree (Araucaria angustifolia), cedar (Cedrus sp.), olive (Oleaceae), gum (Myrtaceae) and waxberry (Morella sp.). Weeds identified were pigweed (Amaranthus sp.), the daisy family (Asteraceae), erica (Ericaceae), dandelion (Taraxacum sp.) and mezereum (Thymelaeaceae sp.). Moulds were low.

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