Insecticide resistance profiles in malaria vector populations from Sud-Kivu in the Democratic Republic of the Congo.

BACKGROUND: Insecticide resistance has become a widespread problem causing a decline in the effectiveness of vector control tools in sub-Saharan Africa. In this situation, ongoing monitoring of vector susceptibility to insecticides is encouraged by the WHO to guide national malaria control programmes. Our study was conducted from April to November 2018 in Tchonka (Sud-Kivu, Democratic Republic of the Congo) and reported primary data on the resistance status of Anopheles funestus and Anopheles gambiae. METHODS: Insecticide susceptibility bioassays were performed on wild populations of A. funestus and A. gambiae using WHO insecticide-impregnated papers at discriminating concentration. In addition, PCR was performed to identify mosquito species and to detect kdr and ace-1R mutations involved in insecticide resistance. RESULTS: Bioassay results show resistance to all tested insecticides except pirimiphos-methyl, propoxur, fenitrothion and malathion with a mortality rate ranging from 95.48 to 99.86%. The addition of piperonyl butoxide (PBO) increased the susceptibility of vectors to deltamethrin and alpha-cypermethrin by exhibiting a mortality ranging from 91.50 to 95.86%. The kdr mutation was detected at high frequencies (approximately 0.98) within A. gambiae while ace-1R was not detected. CONCLUSIONS: This study provides useful data on the insecticide resistance profiles of malaria vector populations to better manage vector control. Our results highlight that, despite the high level of resistance, organophosphorus compounds and pyrethroids + PBO remain effective against the vectors.

The lavage fluid from a patient with alveolar proteinosis inhibits the in vitro chemiluminescence response and arachidonic acid metabolism of normal guinea pig alveolar macrophages.

Pulmonary alveolar proteinosis is characterized by the accumulation of a lipoproteinaceous material within the alveoli of the lung. It is well established that patients with pulmonary alveolar proteinosis have a high incidence of complicating pulmonary infections possibly resulting from defects of antibacterial functions of alveolar macrophages. Moreover, for unclear reasons, an inflammatory response in the airways is frequently absent. In order to investigate the role of the lipoproteinaceous material in these two patterns, we tested the in vitro effects of a lavage fluid from a human pulmonary alveolar proteinosis on the secretion of reactive oxygen intermediates and arachidonic acid metabolites by normal guinea pig alveolar macrophages. After incubation with the lipoproteinaceous material, the luminol-enhanced chemiluminescence of zymosan-triggered alveolar macrophages was reduced in a dose-dependent fashion. The lipoproteinaceous material similarly reduced the chemiluminescence response in a cell-free xanthine-xanthine oxidase system generating superoxide anions. This latter observation suggests that the lipoproteinaceous material acts as a scavenger for superoxide anions produced by alveolar macrophages. Its purified protein or phospholipid fractions also resulted in a general inhibition of the secretion of arachidonic acid metabolites by alveolar macrophages challenged in vitro with zymosan. Our results suggest that the alveolar filling material of pulmonary alveolar proteinosis may inhibit the action of antibacterial and/or proinflammatory agents produced by alveolar macrophages. We speculate that such effects of the lipoproteinaceous material may play a role in vivo in the high incidence of pulmonary infections and in the absence of discernible interstitial or intraalveolar inflammation seen in pulmonary alveolar proteinosis.

Amyotrophic lateral sclerosis presenting with sleep hypopnea syndrome.

Described is a 67-year-old man whose initial symptoms evoked an obesity-hypoventilation syndrome. Polysomnography showed hypopneas associated with O2 desaturation episodes, and no apnea; maximal changes were noted during REM sleep. A few months later, in spite of marked weight loss, acute alveolar hypoventilation occurred and necessitated mechanical ventilatory support. Tracheostomy was performed. The patient appeared to be dependent on nocturnal ventilatory assistance. Diaphragmatic paralysis was noted in addition to clinical and electrodiagnostic evidence of amyotrophic lateral sclerosis. While the patient was not ventilated, a nocturnal recording of SaO2 again revealed desaturation episodes partly corrected by O2 2 L/min administered through the tracheostomy tube. With volume-controlled ventilation, desaturations completely disappeared, although no oxygen enrichment of the air was provided. We speculate that sleep disorders with hypopneas and O2 desaturation episodes were the initial symptoms of amyotrophic lateral sclerosis. This leads us to suggest that nonspecific respiratory muscle fatigue frequently seen in COPD might be included in the hypothetic causes of nocturnal hypoxemia.