Effects of Allium Sativum Ethanolic Extract on Trypanosoma brucei brucei Parasites' Morphometric Parameters and Clinical Outcome in White Albino Laboratory Rats

BACKGROUND Trypanosomosis affects humans as well as wild and domestic vertebrates, yet has no successful prophylaxis, chemotherapy nor cure. OBJECTIVES The study was to investigate the effects of Allium sativum extract on Trypanosoma brucei brucei parasites' morphometric parameters, parasitemia and the clinical outcome in white infected Albino laboratory rats in order to determine its trypanocidal effects. METHODOLOGY The study was conducted at the department of Biological Sciences Laboratory of the Moi University Eldoret. Thirty two (32) mature rats randomly divided into four groups (M, N, P and Q) were kept in four (4) cages in a well ventilated room, with adequate light supply in the day. Sixteen (16) rats were infected with T. b. brucei (1.0 x 104 parasites per rat); eight (8) of which (Group N) were treated with the A. sativum ethanolic extract on day 5 and day 9 after infection, while the other eight (8)rats (Group Q) received saline treatment on the same days. Sixteen (16) non-infected rats (controls) were also divided into two groups of eight rats each (P and M) and treated as in group N and Q, respectively. The rats were obtained from University of Nairobi, Chiromo Campus. RESULTS All infected rats became parasitemic two days after infection and reached peak levels on day 4 and 5 post infection. Parasitemia in saline treated infected rats fluctuated between 4025.5 ± 0.05 - 5544.4 ± 0.05 parasites per 200WBC whereas in the extract treated rats parasitemia declined from 6976.6 ± 0.05 - 311.0 ± 0.05 parasites per 200WBC after the first treatment. Uninfected saline treated rats maintained normal Hb level (10.6g/L to 11.8g/L) as compared to the uninfected extract treated rats' whose Hb levels was at 13.41g/L to 14.36g/L. The haemoglobin level changed to 8.0g/L four days after the infection in the group N rats before rising to 10.2g/L on day 8 post-infection following the extract treatments. Group Q rats' Hb declined to 6.43g/L by the end of the study. RBC count of the infected saline treated rats declined to 3.38 x 106/µL as compared to 4.93-7.61 x 106/µL in the normal rats by 11 days postinfection.There was however no significant change in WBC, temperature and weight between the saline extract treated rats. The extract produced a shrinking effect on the parasite's body with some of the morphometric parameters appearing significantly (P<0.05) reduced as observed under a microscope with ocular and stage micrometer scale. The mean nucleus, posterior ends to nucleus centre, the nucleus centre to the anterior end and the body length were reduced from 2.41µm to 1.42µm(P=0.00), 4.42µm to 3.68µm(P=0.017) , 4.65µm to 4.18µm(P=0.001) and 8.58µm to 7.19µm(P=0.001) respectively. CONCLUSION In conclusion it was evident that, A. sativum ethanolic extract exhibited Trypanocidal effects that can be exploited to control clinical progression of Trypanosomosis in rats. In addition, the data presented demonstrates the plant extract had the potential to improve the red and white blood cell indices reducing parasitaemia following T. b. brucei infection. These findings suggest that, the garlic extract affected the plasma membrane of the parasites since shrinking was only possible with disrupted membrane biochemistry

Anti-trypanosomal Activity of Potential Inhibitors of Trypanosoma brucei Glycolytic Pathway Enzymes Selected by Docking Studies

Human African trypanosomiasis (HAT); a potentially fatal protozoan infection caused by tsetse-fl mediated transmission of Trypanosoma brucei (T. Brucei); is largely recognized as a neglected disease. The repertoire of drugs that is effective against the infection is limited and all drugs have several drawbacks including high level of toxicity; difficult administration regimens; and the resurgence of resistance. At present the biology of the parasite is well studied and a number of technologies are now available which can aid in the identifiation of potential drug targets. This review identifis putative inhibitors of trypanosomal glycolytic enzymes

In vivo antitrypanosomal effects of some ethnomedicinal plants from Nupeland of North Central Nigeria

Abstract: Four medicinal plants Acacia nilotica, Bombax buonopozense, Terminalia avicennioides and Zanthoxylum zanthoxyloides traditionally used for treatment of sleeping sickness in Nupeland were investigated for in vivo antitrypanosomal activity. Methanol extracts of different parts of each plant (stem barks and fruits) were obtained and evaluated for their in vivo antitrypanosomal activities against Trypanosoma brucei brucei. Phytochemical screening of the methanol extracts of each plant were performed by standard procedures. Methanol extracts of A. nilotica (stem bark), B. buonopozense (stem bark), T. avicennioides (round fruit) and Z. zanthoxyloides (stem bark) were effective on trypanosomes. The extracts of A. nilotica and B. buonopozense exhibited antitrypanosomal effects at 200 and 300 mg/kg body weight respectively. Doses were able to clear the parasites from circulation within 6 and 7 days of treatment respectively with prolonging survival period of up to 30 days. While the extracts of T. avicennioides and Z. zanthoxyloides showed trypanostatic effects and could not clear the parasites completely. The methanol extracts of these plants contain metabolites that are associated with antitrypanosomal effects; therefore, these medicinal plants may be sources of new compounds that may be active against T. b. brucei. This study has also justified the claim that some medicinal plants of Nupeland possess antitrypanosomal activity and could be useful in the management of trypanosomiasis

Characterisation of the Trypanosoma brucei rhodesiense isolates from Tanzania using serum resistance associated gene as molecular marker

Serum resistance associated (SRA) gene has been found to confer resistance to the innate trypanolytic factor (TLF) found in normal human serum; thus allowing Trypanosoma brucei brucei to survive exposure to normal human serum. This study was carried out to examine the presence of SRA gene and identify the origin of T. b. rhodesiense isolates from three districts in Tanzania, namely Kibondo, Kasulu and Urambo. Twenty-six T. b. rhodesiense isolates and two references T. b. rhodesiense isolates from Kenya were examined for SRA gene using simple Polymerase Chain Reaction technique. The gene was found to be present in all 26 T. b. rhodesiense isolates including the two references isolates from Kenya. The SRA gene was confirmed to be specific to T. b. rhodesiense since it could not be amplified from all other Trypanozoon including T. b. gambiense; and gave an amplified fragment of the expected size (3.9kb), confirming that all these isolates were T. b. rhodesiense of the northern variant. Although the geographic distributions of T. b. gambiense and T. b. rhodesiense are clearly localized to west/central Africa and eastern Africa, respectively, natural movement of people and recent influx of large number of refugees into Tanzania from the Democratic Republic of Congo, could have brought T. b. gambiense in western Tanzania. The overlap in distribution of both of these pathogenic sub-species could result in erroneous diagnoses since both trypanosome sub-species are morphologically identical, and currently serologic methods have low specificity. Both the susceptible and resistant T.b. rhodesiense isolates possessed the SRA gene suggesting that there is no correlation between drug resistance and presence of SRA gene. The use of SRA gene helps to confirm the identity and diversity of some of the isolates resistant to various drugs.

In Vivo Trypanocidal Effect of Ethanolic Leaf Extract of Khaya Nyasica Stapf

The ethanolic and aqueous crude extracts of Khaya nyasica Stapf. (Meliaceae) leaves and stem bark were screened for their trypanocidal effects against Trypanosoma brucei brucei in mice. At a single 25mg dose; the ethanolic leaf extract demonstrated trypanocidal activity by reducing parasitaemia from day 8 post treatment. There was no observed reduction of parasitaemia in solvent treated and untreated mice. The best trypanocidal effect was achieved at the same single 25mg dose when treatment commenced simultaneously with inoculation of trypanosomes by delaying development of parasitaemia by three days and reducing it from day 9 post treatment. Further bio-guided fractionation studies of ethanolic fractions is recommended to evaluate the observed trypanocidal effect of the plant and identify the active principle

Drug resistance in Trypanosoma brucei spp.; the causative agents of sleeping sickness in man and nagana in cattle

Drug resistance in pathogenic trypanosomes threatens successful control of fatal sleeping sickness in man and hinders economic livestock production in sub-Saharan Africa. We report on the occurrence and development of drug resistance; and discuss the genetic basis of such resistance in Trypanosoma brucei. Understanding these mechanisms at the molecular level will enable improved management of existing drugs and provide valuable clues to the development of new trypanocides

East African Trypanosomiasis in Nkhotakota District

A marked increase in trypanosomiasis has been seen at Nkhotakota District Hospital since September 1989. This report presents background information; the extent of the recent outbreak and suggested revised treatment protocol. Suggestions are made for preventative measures against the spread of trypanosomiasis

Sleeping sickness surveys: game reserve adjacent to villages in Malawi

Although tsetse control measures were discontinued in Malawi in the early 1950s; the prevalence of sleeping sickness apparently remained at low levels. A sleeping sickness survey conducted in 1987 to 1989 revealed a prevalence of the disease of 3 percent (103/3000). Seven percent (215/3000) of the individuals tested were positive for malaria. 87 individuals traced 2 years after hospital discharge were found well and active in their villages. Four died in villages after hospital treatment. Three relapsed and were readmitted to hospital. Sera from 160 game ranger volunteers and from 82 suspected cases of Rhodesian sleeping sickness were tested by use of ELISA; IFAT and CATT. ELISA and CATT; though not specific; proved to be useful tests for mass screening for human trypanosomiasis. Thick blood smear was found to be the best diagnostic method in this survey