Entomological & biochemical studies on the etiology of maleria

Abstract

Malaria, a disease caused by various species of Plasmodium is a major health problem in many developing countries. In the present studies we seek to present the intensity of malaria resurgence in Quetta. A 36 month longitudinal assessment of the vectors, Anopheles culcifacies and Anopheles stephensi revealed the inclination of changing vector in Quetta suburbs. It was further documented that the seasonal appearance of Anopheles species is correlated with fluctuation in meteorological conditions. For a better assessment the results were compared with the data provided by malaria control center. The magnitude of malaria was detected by observing the number of positive blood slides for parasitaemia. An alarming increase of malaria incidence was observed. Plasmodium vivax was the predominant infecting species during April and May, and also prevailed during the transmission season; whereas P. falciparum was the most common infecting species later in the transmission season. Occurrence of P. vivax trophozoite gametocyte rates were much higher than P.falciparum gametocytes. The biochemical analysis of the blood from 100 Afghan malaria patients revealed that the high malaria incidence in Afghans was not due to the deficiency of glucose-6-phosphate dehydrogenase. Liver function disturbances were shown by increase in bilirubin from 1-2 mgs% amongst 14% patients while the range of serum glutamate pyruvate transaminase raised to a high of 60 u/l amongst 50% patients. The increase was comparatively greater in falciparum infections. The humoral response was found not to be very active after the antigenic stimulation. On the beginning of parasitaemia the malaria antibodies comprising of the Immunoglobulins (Ig), IgG, IgA and IgM were confirmed to rise in various degrees which ranged from 34-48%. A 4% resistance of malaria parasite to nivaquine and primaquine ranging within R1 and R11 types was also observed. Therefore, efforts were made to develop a drug from the traditionally known herb Gentiana Olivieri used for medicinal purposes, such as fever, supposed to be caused by malaria. The chemical analysis for fatty acid composition as identified by Gas Chromatography- Mass Spectrometry revealed to contain six fatty acids amongst which five were found to be saturated and one unsaturated. Two alkaloids Gentianadine and Gentianine were also purified and identified with the help of UV, IR, High Resolution Mass Spectrometry and Proton and 13C-NMR. Gentianine was isolated in a significantly large amount to carry out necessary biological and pharmacological assays required for the development of a drug. Toxicological evaluation in shrimp nauplii proved it to be non-toxic. However, chronic toxic studies at higher doses in rats indicated a slight elevation of serum glutamate pyruvate transaminase and relatively greater increase of Lactate dehydrogenase. Hypo or hyperglycemia was not observed even at higher doses. Biological assays of the pure alkaloid revealed its strong antibacterial activity against four gram negative bacteria. Its activity was also remarkable against seven of the ten fungi tested. Gentianine was found to be an effective hypotensive agent and caused a decrease of systolic, diastolic and mean arterial blood pressure (50%) in normotensive rats at a dose of 10 mgs. It was also found to be a potent diuretic, having a significant aquaretic effect with elevated electrolyte concentration. Analysis of the UV spectra proved the occurrence of binding between the purified cell surface glycoproteins and the pure compound. The pure and crude samples were very kindly send by Dr. Ata-ur-Rehman to USA for the assurance of antimalarial activity, since the facility of parasite culture was not established in Pakistan.