Prevention of snail miracidia interactions using Phytolacca dodecandra (L'Herit) (endod) as a miracidiacide: an alternative approach to the focal control of schistosomiasis

The efficacy of soap against schistosome cercariae: A systematic review

BACKGROUND

Schistosomiasis is a parasitic disease that is endemic in 78 countries and affects almost 240 million people worldwide. It has been acknowledged that an integrated approach that goes beyond drug treatment is needed to achieve control and eventual elimination of the disease. Improving hygiene has been encouraged by World Health Organisation, and one aspect of good hygiene is using soap during water-contact activities, such as bathing and doing laundry. This hygiene practice might directly reduce the skin exposure to cercariae at transmission sites. A systematic review was carried out to investigate the efficacy of soap against schistosome cercariae and to identify the knowledge gaps surrounding this topic.

METHODOLOGY

Six online databases were searched between 5th and 8th July of 2021. Records returned from these databases were screened to remove duplicates, and the remaining records were classified by reading titles, abstracts, and full texts to identify the included studies. The results were categorised into two groups based on two different protective mechanisms of soap (namely, damage to cercariae and protection of skin).

CONCLUSIONS

Limited research has been conducted on the efficacy of soap against schistosome cercariae and only 11 studies met the criteria to be included in this review. The review demonstrates that soap has the potential of protecting people against schistosome cercariae and there are two protective aspects: (1) soap affects cercariae adversely; (2) soap on the skin prevents cercariae from penetrating the skin, developing into adult worms and producing eggs. Both aspects of protection were influenced by many factors, but the differences in the reported experimental conditions, such as the cercarial endpoint measurement used and the cercaria numbers used per water sample, lead to low comparability between the previous studies. This review indicates that more evidence is needed to inform hygiene advice for people living in schistosomiasis endemic areas.

Triterpenoid and Saponin Rich Phytolacca dodecandra L'Herit (Endod): A Review on Its Phytochemistry and Pharmacological Properties

Phytolacca dodecandra L'Herit (Endod) is the most extensively studied plant among 35 known species in the genus Phytolacca (Family: Phytolaccaceae). The plant has been used as a viable treatment for various ailments, such as malaria, rabies, ascariasis, and skin disorders, in many parts of Africa. In Ethiopia, the dried and powdered Endod berries have been used for a long period of time as a detergent to clean clothes. Since the discovery of the molluscicidal activities of its berries more than five decades ago, P. dodecandra has been a research focus worldwide and several phytochemicals mainly of triterpenoids and saponins were reported. Additionally, various biological activities, including larvicidal, insecticidal, antibacterial, antifungal, and anti-inflammatory activities of its isolated compounds and crude extracts were investigated. Furthermore, some of the findings from pharmacological and phytochemical investigations were patented to be used in various medicinal formulations. The plant is still the subject of many investigations and hence, a thorough up-to-date review is required to provide comprehensive information needed for future exploitation of the plant. In this review, the phytochemical compositions and pharmacological activities are comprehensively addressed and discussed in details.

Phytolacca dodecandra (Phytolaccaceae) Root Extract Exhibits Antioxidant and Hepatoprotective Activities in Mice with CCl4-Induced Acute Liver Damage

BACKGROUND

The liver is a hub of metabolism and detoxification of substances. Since many redox reactions take place in the liver, it is prone to oxidative damage. Unlike conventional agents, botanicals act through several mechanisms in preventing oxidative damage. Among these Phytolacca dodecandra is the most commonly used agent in Ethiopian folk medicine.

OBJECTIVE

To evaluate antioxidant and hepatoprotective activities of the 80% methanol extract of P. dodecandra root.

METHODS

Male mice were divided into six groups and treated accordingly. Negative control was given 2% Tween 80, toxicant control administered with carbon tetrachloride (CCl4), positive control treated with silymarin 100 mg/kg, and test groups were treated with 100, 200, and 400 mg/kg of the extract. Then, serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, albumin, total protein, and bilirubin were determined. Determination of the change in body weight and liver weight, histopathologic examination of the liver, and in vitro and in vivo antioxidant assays were also carried out.

RESULTS

The levels of ALP, ALT, AST, GGT, LDH, and bilirubin were significantly reduced, while albumin and total protein were significantly increased after treatment with P. dodecandra root extract at the doses of 200 and 400 mg/kg in CCl4 intoxicated mice. Cholesterol metabolism and lipoprotein synthesis capabilities of the liver of mice were also returned to normal in the two doses. Besides, the 200 and 400 mg/kg doses were able to return the normal architecture and morphology of hepatocytes. Furthermore, the plant extract was found to scavenge free radicals in vitro and inhibit lipid peroxidation in vivo.

CONCLUSION

The results suggest that the 80% methanol extract of P. dodecandra root can be used for the management of liver disease.

Pharmacology, Phytochemistry, and Toxicity Profiles of Phytolacca dodecandra L'Hér: A Scoping Review

Introduction

Phytolacca dodecandra L'Hér. is a native plant of sub-Saharan Africa and Madagascar which is traditionally used for various ailments. Concerned with the scope of the available evidence, we designed a scoping review to critically analyze scientific evidence on P dodecandra's pharmacology, toxicity, and phytochemistry to validate its ethnomedical use.

Methods

We searched without language restriction in MEDLINE, Google Scholar, Scopus, Embase, and Web of Science through December 2019. Both published and unpublished articles were assessed for relevance and reviewed.

Results

Of 600 articles retrieved through database search, a total of 48 articles were finally included. The butanol extract of berries was more potent molluscicidal than aqueous extract. The berries had also miracidial, anthelmintic, antifungal activity, and antibacterial effect against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Salmonella spp. The methanol extracts of roots had an antifungal effect against Candida albicans, Cryptococcus neoformans, Microsporum gypseum, and Trichophyton mentagrophytes. Phytolacca dodecandra was toxic to aquatic invertebrate and fish. The fishes were up to 4 times more sensitive than snails. Saponins were the main phytoconstituent isolated from berries. Terpenoid and phenolic were abundant in leaves and bark extracts.

Conclusions

Studies validated the traditional use of P dodecandra against snails, worms, and various bacterial and fungal infections. Limited phytochemical data call for future research to focus on isolation of compounds; test their toxicity and activity; and establish mechanism of action.

Larvicidal effect of Endod (Phytolacca dodecandra) seed products against Anopheles arabiensis (Diptera: Culicidae) in Ethiopia

OBJECTIVE

The purpose of the present study was to determine the larvicidal effect of 'Endod' (Phytolacca dodecandra) seed products on Anopheles arabiensis, in Ethiopia.

RESULTS

Experimental study was conducted using a total of 2400 third instars larvae of A. arabiensis. The seed products P. dodecandra showed larvicidal activity against 3rd-stage larvae of both the laboratory and field population of A. arabiensis. The LC99 values for P. dodecandra's seed powder and its extract form against the laboratory reared larvae were 121.07, and 616.46 mg/l, respectively. The LC50 and LC95 values were also determined.

Getting a GRiPP on everyday schistosomiasis: experience from Zimbabwe

Schistosomiasis, commonly known as bilharzia, is a parasitic disease prevalent in Africa, Asia and South America. The majority of the cases occur in Sub-Saharan Africa where schistosomiasis is a major public health problem impacting on child health and development as well as adult health when infections become chronic. Control of schistosomiasis is by treatment of infected people with the antihelminthic drug praziquantel. Current schistosome control programmes advocated by the World Health Assembly in 2001 are aimed at regular school-based integrated deworming strategies in order to reduce development of severe morbidity, promote school health and to improve cognitive potential of children. Several countries in Africa have now embarked on national scale deworming programmes treating millions of children exposed to schistosomiasis in endemic areas without prior diagnosis of infection through mass drug administration programmes. Implementing such control programmes requires a concerted effort between scientists, policy makers, health practitioners and several other stake holders and of course a receptive community. This paper considers the contributions to global schistosome control efforts made by research conducted in Zimbabwe and the historical context and developments leading to the national schistosomiasis control programme in Zimbabwe giving an example of Getting Research into Policy and Practice.

The roles of water, sanitation and hygiene in reducing schistosomiasis: a review

Schistosomiasis is a disease caused by infection with blood flukes of the genus Schistosoma. Transmission of, and exposure to, the parasite result from faecal or urinary contamination of freshwater containing intermediate host snails, and dermal contact with the same water. The World Health Assembly resolution 65.21 from May 2012 urges member states to eliminate schistosomiasis through preventive chemotherapy (i.e. periodic large-scale administration of the antischistosomal drug praziquantel to school-aged children and other high-risk groups), provision of water, sanitation and hygiene (WASH) and snail control. However, control measures focus almost exclusively on preventive chemotherapy, while only few studies made an attempt to determine the impact of upgraded access to safe water, adequate sanitation and good hygiene on schistosome transmission. We recently completed a systematic review and meta-analysis pertaining to WASH and schistosomiasis and found that people with safe water and adequate sanitation have significantly lower odds of a Schistosoma infection. Importantly though, the transmission of schistosomiasis is deeply entrenched in social-ecological systems, and hence is governed by setting-specific cultural and environmental factors that determine human behaviour and snail populations. Here, we provide a comprehensive review of the literature, which explores the transmission routes of schistosomes, particularly focussing on how these might be disrupted with WASH-related technologies and human behaviour. Additionally, future research directions in this area are highlighted.

Control of Biomphalaria pfeifferi population and schistosomiasis transmission in Ethiopia using the soap berry endod (Phytolacca dodecandra), with special emphasis on application methods

The endod (Phytolacca dodecandra)-based schistosomiasis mansoni control project was implemented in Ethiopia between 1994 and 1999. The aim was to develop an effective, cheap and sustainable method of controlling schistosomiasis. First, different formulations of the Ethiopian endod strain 44 (E-44) were compared for potency in the laboratory. Secondly, spray and drip-feeding methods were compared for simplicity and effectiveness in the field. Lastly, the efficacy of endod powder soap was compared with the endod spray method. In Bati stream, endod powder soap was distributed to the residents every weekend at laundry sites. In Worke stream, endod was sprayed along a 1-km stretch of the stream at 3-month intervals. No endod was applied in Harbu stream. The immediate and long-term effects of endod application on the snail population and schistosomal infection were determined. Using the spray method, 100% snail mortality could be obtained, and it was simpler and more effective than the drip-feeding method. Snail mortality ranged from 20 to 100% using endod soap. There was a progressive decline in the snail population and infection in Bati stream compared with Worke stream, mainly due to sustained use of endod soap. The advantages and disadvantages of the different endod delivery systems are discussed.

Implementation of Human Schistosomiasis Control: Challenges and Prospects

Schistosomiasis is a major disease of public health importance in humans occurring in over 70 countries of the tropics and sub-tropics. In this chapter, the history of the control of schistosomiasis is briefly discussed and current methods of control of schistosomiasis are reviewed; including mollusciciding, biological control of the intermediate snail hosts, the development of drugs to kill the adult worms, provision of clean water and health education, with a focus on the African situation. Since an effective vaccine against schistosomiasis is lacking, the emphasis today is placed on the drug praziquantel (PZQ). The marked reduction in the cost of PZQ together with the support of the Bill and Melinda Gates Foundation has enabled the drug to be used more widely in sub-Saharan Africa. Nevertheless, with the possibility of resistance to praziquantel emerging, the potential role of other drugs, such as artemether, in the control of schistosomiasis is examined. The World Health Organization (WHO) anticipates that at least 75% of all schoolchildren at risk of morbidity from schistosomiasis will be treated by 2010, with the aim of reversing morbidity. The importance of recent international initiatives such as the Schistosomiasis Control Initiative (SCI) working in Mali, Niger, Burkina Faso, Zambia, Tanzania and Uganda is recognised. There are benefits to integrating the control of schistosomiasis with other disease control programmes, such as gastrointestinal helminths and/or lymphatic filariasis (LF), since this markedly reduces the cost of delivery of the treatment. Countries that are situated on the perimeter of the distribution of schistosomiasis have either achieved or have made progress towards the elimination of the disease. For control programmes to be successful in areas such as sub-Saharan Africa, it is absolutely essential that these programmes are sustainable. Thus, it will be vital for Ministries of Health and Education to budget for the control of diseases of poverty in addition to school health, and to utilise funds from a range of sources, such as, government funds, pooled donor contributions, or bilateral and international agencies.

Toxicology of a potential molluscicide derived from the plant Solanum xanthocarpum: a preliminary study

A potential molluscicidal extract, obtained from the indigenous Chinese plant Solanum xanthocarpum (Schrad. and Wendl), was tested for toxicity against snails and fish in static, acute-toxicity tests. The extract had a significant effect on mature and young snails of the amphibious Asian freshwater prosobranch Oncomelania hupensis (Gredler) and also on mature specimens of the freshwater pulmonate snails Biomphalaria glabrata (Say) and Lymnaea stagnalis (Linnaeus). The minimum dose that produced 100% mortality of snails exposed for 48h, 4.321mg/litre, is much less than the threshold, of 100mg/litre, set for a potential molluscicide by the World Health Organization. In contrast, the minimum concentration producing 100% mortality in the fish Gobiocypris rarus (Ye and Fu) was 17.28mg/litre. The extract also limited the extent of water-leaving by snails exposed to it, an important feature for the control of amphibious snails. This extract thus represents a promising plant-derived molluscicide which is worthy of further investigation.