Abstract
Abstract : The different life stages of Oreochromis mossambicus and their response to chronic exposure to pharmaceuticals: The HIV anti-retroviral drug nevirapine and the antibiotics sulfamethoxazole and trimethoprim Human pharmaceuticals and their metabolites in aquatic environments are considered as “contaminants of emerging concerns” as there is limited information on their behaviour in the environment. Consequently, their potential unintended effects on aquatic animals including fish are still largely unknown. The anti-retroviral drug nevirapine (NVP) and the antibiotics sulfamethoxazole (SMX) and trimethoprim (TMP) are amongst the most regular prescribed pharmaceuticals in South Africa. These drugs are also frequently detected in wastewater treatment plants’ effluents and in surface waters across Africa. Nevirapine is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used as a first-line treatment for the prevention of the Human Immunodeficiency Virus (HIV). The antibiotics SMX and TMP are amongst the most consumed antimicrobials globally because they are cheaper, and they have a broad range antimicrobial activity. They are commonly used in human health care, in animal farming and in crops production. In humans, they are combined in one pill, co-trimoxazole, which is part of the HIV therapy to treat and prevent opportunistic infections. Despite the health benefits NVP, SMX and TMP are listed amongst the top 10 human pharmaceuticals associated with liver toxicity and kidney injury. In addition, SMX and TMP are amongst the antibiotics suspected to cause antimicrobial resistance worldwide. Few studies are available on the potential effects of NVP, SMX, TMP and their mixtures on indigenous fish species in African surface waters. This study investigated the chronic effects of NVP as a single toxicant and in a mixture with SMX and TMP on the different life stages of Oreochromis mossambicus in a laboratory controlled exposure. Environmentally relevant concentrations of the pharmaceuticals in African surface waters from published literature were used in a static renewal system. Growth parameters (weight, length, condition factor and specific growth rate) were used to investigate the effects of the pharmaceuticals on...
D.Phil. (Aquatic Health)