Efficacy of Photogem® (Hematoporphyrin Derivative) as a Photoactivatable Larvicide against Aedes aegypti (Diptera: Culicidae) Larvae

Abstract

Dengue vector is responsible for millions of deaths every year and has caused disastrous impacts on health systems. The continuous use of chemical insecticides, such as carbamates, pyrethroids and organophosphates generates resistant populations of the mosquito, therefore, new control methods must be investigated. The joint action of the population and guidelines for preventing the reproduction of the mosquito associated with the use of photoactivatable insecticides can be the alternative for the control of epidemiological outbreaks in affected regions. In this study, the photo-larvicidal activity of Photogem ® (PG), a derivative of hematoporphyrin, was investigated against 2 nd -early 3 rd instar of Aedes aegypti larvae (Diptera: Culicidae) under different lighting conditions (artificial lighting system and sunlight). The dynamics of PG accumulation was characterized by CLSM (confocal laser scanning microscopy) and total time PG eliminationin solution was investigated by ultraviolet-visible spectrophotometry. The maximum photo-activity of PG was observed in 0.5 h under sunlight exposure which achieved 100% larval mortality. Fluorescence images showed a uniform distribution of PG along the digestive tract. PG remained stable in the sunlight for 48 h and in an artificial lighting system for longer periods, therefore, it can be used for the control of Aedes aegypti larvae as a new alternative to chemical insecticides. The method is considered environmentally friendly due to its rapid degradation in the presence of light. Further studies are required, so that the potential of the technique can be explored in real breeding places.

A look at photodynamic inactivation as a tool for pests and vector-borne diseases control

“…In 2017, Souza et al [74] (Entry 7, table 2) evaluated the photolarvicidal efficiency of Photogem ® (PG), a HP derivative, was evaluated in 2nd and 3rd instar larvae of A. aegypti (Diptera: Culicidae) under artificial lighting with fluorescent lamps and sunlight . The authors observed mortality rates of 71, 91 and 100% for PG in aqueous medium at concentrations of 20, 40 and 80 µg ml −1 , respectively, incubated for 12 h and exposed to the sun in the intensity range of 30-60 mW cm −2 .…”

Investigation of Hibiscus sabdariffa as a new eco-friendly photo-larvicidal natural product for the control of mosquitoes

“…In Nigeria, it is estimated that 80 to 120 million people are at risk of the disease (Hotez et al, 2012). Viral encephalitis is an inflammation of the brain parenchyma that is indicated by fever, headache and in extreme cases, seizures (fits), confusion, drowsiness, and loss of consciousness, and even coma (Saema & Michael, 2020). The West Nile Fever is a flavivirus (a group of single stranded RNA viruses that cause severe endemic infections and epidemics on a global scale) that has similarities with the viruses that cause St. Louis encephalitis, Japanese encephalitis, and yellow fever and infects humans, horses, and a variety of bird species.…”