Ethnobotanical survey of plants traditionally used to treat lymphatic lariasis in southern, Western and northwestern provinces of Zambia

Lymphatic lariasis is caused by three thread-like parasitic worms, called lariae. The infection damages the lymphatic system, increasing the risk for secondary infections and complications. Folks rely on Traditional healers as rst line of care for most LF patients living in the community, most patients only go to the health facility once the symptoms have progressed and the pain worsened. This present review discuses some of medicinal plants that are used to treat LF in Southern, Western and Northwestern provinces of Zambia. The results of the survey found 17 plants from 15 different families were being used to treat LF, with the oral and topical route being the most common routes administration.


Introduction
Lymphatic lariasis is caused by three thread-like parasitic worms, called lariae. The species Wuchereria bancrofti is the most prevalent worldwide, Brugia malayi is found mostly in eastern Asia, and Brugia timori is con ned to East Timor and adjacent islands. Filarial parasites in their adult stage live in the lymphatic system. The worms have an estimated active reproductive span of 4-6 years, producing millions of small immature larvae, micro lariae, which circulate in the peripheral blood. They are transmitted from person to person by several species of mosquito (WHO, 2013) Approximately 15 million people globally are affected by lymphatic lariasis related lymphoedema (or elephantiasis), which includes swelling of the limbs, breasts or genitals, and almost 25 million men are affected by urogenital swelling, primarily scrotal hydrocoele (Michael, 1996). Although these clinical manifestations are not often fatal, they lead to the ranking of lymphatic lariasis as one of the world's leading causes of permanent and long-term disability (WHO, 1995) Lymphatic lariasis infection can occur early in life. In some areas, about 30% of children are infected before the age of 4 years (Simonsen PE et al., 1996, Lammie PJ et al, 1998, and, while the clinical disease usually appears later in life, subclinical damage starts at an early age (WHO, 2010) The World Health Organization (WHO) baseline data in the year 2000 indicated that more than 120 million people were infected globally, and approximately 40 million suffered from the stigmatizing and disabling clinical manifestations of the disease, including 15 million who have lymphoedema and 25 million men who have urogenital swelling, principally scrotal hydrocele (WHO, 2019A). In 2000,about 40 % of LF infected people were from Sub Sahara Africa, with cases ranging from 46 to 51 million, and an estimated at-risk population of 432 million people (Ichimori et al., 2014) and in 2018,the total estimated at-risk population requiring intervention in Africa was 341 million (WHO, 2019B) One hundred and twenty million people in at least eighty countries are infected with the parasites associated with lymphatic lariasis. 90% of this infection is caused by W. bancrofti. Most of the remaining cases are due to Brugia malayi (B. malayi). In addition, one billion people (20% of the world's population) are estimated to be at risk for infection (Leite et al., 2010, Addiss et al., 2010. Although 80 countries are known to be endemic areas, about 70% of infected cases are in India, Nigeria (Okon et al., 2010), Bangladesh and Indonesia. Lymphatic lariasis is endemic in 32 of the world's 38 least developed countries (Chu, 2010).
A signi cant proportion of the public health problem represented by lymphatic lariasis is due to impairment and disability related to lymphoedema (elephantiasis) and hydrocoele. Therefore, national programmes focus on managing morbidity and preventing disability. These activities will not only help lymphatic lariasis patients but can improve coverage with drugs (Cantey et al., 2010).
Management of morbidity and disability in lymphatic lariasis require a broad strategy involving both secondary and tertiary prevention. Secondary prevention includes simple hygiene measures, such as basic skin care, to prevent ADLA and progression of lymphoedema to elephantiasis (Dreyer G et al., 2002, WHO, 2010. Lymphatic lariasis infection damages the lymphatic system, increasing the risk for secondary infections and complications. An estimated 40 million people globally have clinically signi cant manifestations of lymphatic lariasis-predominantly lymphoedema and hydrocoele-accounting for 5.9 million disabilityadjusted life years (WHO, 1995) In Zambia, LF is also a public health concern, as 87 of 118 districts are considered endemic with the prevalence of the circulating larial antigen above 1.5% (MOH, 2019). Results from the LF mapping exercise showed that there were many cases of hydrocele and lymphedema spread across all ten provinces in Zambia (MOH, 2019).

Study area
This ethnobotanical survey was conducted in the three provinces of Zambia namely Southern, Western and Northwestern.

Data collection
Personal interviews were used to gather data on the local plants used to treat LF, these interviews were conducted from November 2020 to May 2021. The other information was obtained through a comprehensive literature search in the Google Scholar and PubMed database using the key word "medicinal plant for treat LF'' and " lariasis herbal drugs''.

Results
After conducting interviews with some local herbalist several plants were identi ed and tabulated as shown below    Some people in rural parts of Zambia stay very far from health facility, for example there are some people that live in Luangwa District which is a very remote and a portion of the district is covered by the Luangwa National Park. As a result, some communities in the district have to travel long distances of up to 20 kilometers and more to the nearest health facility and their access may be inhibited by wildlife attacks such as elephants from the Luangwa National Park. In addition, roads to the health facilities are sometimes impassable and the most common means of transport is bicycles which are inappropriate to transport lymphedema and hydrocele patients. (Maritim et al., 2020), with these challenges people rely mainly on herbal medicine to treat LF and other conditions that are affecting their health.

Conclusion
This study documented some plants that are used traditionally to treat LF in Southern, Western and Northwestern province of Zambia. 17 Plants from 15 different families were recorded and found to be used traditionally to treat LF in Zambia. The plant parts that are being used include roots, stem, leaves, rhizomes, owers and gum, with the oral and topical route being the most commonly used routes.