Prevalence and risk factors of tungiasis among children of Wensho district, southern Ethiopia

Tungiasis, an infestation caused by Tunga penetrans (sand flea or jigger flea), is common in poor communities of the tropical and subtropical part of the world [1]. The Periungual region of the toes is the most preferred site by the flea, although infestation can also occur in hands, elbows, and genital and anal regions [2]. The infestation is more prevalent in children, particularly among 5–10 years old children than in adults [3]. Living with reservoir domestic animals such as cats, dogs and pigs [4], poor personal hygiene, poor sanitation of the housing and residential environment, and lack of foot wear [5–7] are risk factors associated with tungiasis infestation.

Common sequelae associated with Tungiasis are acute and chronic inflammation of toes, fissures, lymphoedema and deformation and loss of toe nails. Severe inflammation, ulceration and fibrosis, and though rarely, death might occur in case of profound infestation [8]. Locally, people extract the mature flea using sterile needle. Moreover, topical application of dimeticones of low viscosity can execute entrenched sand fleas effectively [9]. As a sub-Saharan African country, though infestation is common in Ethiopia, published data on the prevalence and risk factors of tungiasis are scant; only a few studies have reported on the prevalence and/or risk factors of tungiasis in Ethiopia [5, 10, 11]. Hence, this study was designed to determine the prevalence of tungiasis and associated risk factors among children in Wensho district, southern Ethiopia.

Two hundred and fifteen of the 366 children were found to have tungiasis, thus making the prevalence of tungiasis among children in Wensho to be 58.7% (95% CI: 53.7%, 63.8%). The prevalence among males was 57.7% whereas among females it was 60.3%. In 208 (96.7%) of the children with tungiasis, the lesions were located on the feet; however, 12(5.6%) of the children presented with lesions on the hands. A total of 1464 lesions were found on 215 cases with a mean parasite intensity of 6.8 jiggers per a child. Most (74%) of the children with tungiasis had mild infestation, while 50(23.3%) had moderate and 6(2.8%) had heavy/sever infestation (Fig. 2). Most common symptoms among those who were infested were ulcer (70.2%), loss of nails (34%) and deformation of toe or fingers (27.4%) and suppuration (26%).

Different factors were investigated for possible association with tungiasis infestation. These factors included age of the child, sex of the child, educational status of the mother, educational status of the father, family monthly income, floor material of the house in which the children live, types of domestic animals reared by the household (dogs and cats), presence of rats, source of water supply, waste disposal system and use of footwear. After exploring the association of these factors with tungiasis infestation using unadjusted (bivariate) logistic regression model, maternal educational status, floor material of the house, presence of cats in the household, use of footwear and water source were included in the multiple logistic regression model.

This study found a high (58.7%) prevalence of tungiasis in Wensho district, a rural setting, in southern Ethiopia. Significantly higher odds of tungiasis were found among children whose mothers were illiterate or had primary school education compared to children whose mothers had attended secondary education. Children from households owning cats also had higher odds of tungiasis infestation. Furthermore, children who never or rarely use footwear had significantly higher odds of tungiasis than children who always use footwear.

The prevalence of 58.7% found by the current study is much higher than the prevalence rate of 1.2% previously reported from a national survey in Ethiopia [10], 34.7% reported from Yirgacheffe district in southern Ethiopia and 1.6% reported from Brazil [14]. The reason for the difference could be that the current study was done in a dry season when the incidence is supposed to be at its peak. On the other hand, the prevalence found by the current study is comparatively equivalent to or lower than the results reported in children of Cameroon, where the prevalence ranged from 60.5 to 70.2% [15], while this rate is extremely lower than the 97% prevalence reported from Northern Tanzania [16]. Climatic, socioeconomic and cultural factors might have contributed to variations in jigger infestation rate of different epidemiological settings [17].

The apparently high prevalence of tungiasis found by the current study implies that tungiasis is a huge problem with important public health ramifications among children in Wensho. The inflammation in the part of the body where the jigger flea burrows is often unbearable and disturbing. Consequently, people are forced to try to get rid of the flea from the body using needle, thorn or other sharp materials. Yet, such materials are often not sterile and may be shared among people and serve as a way of transmitting blood-borne infections such as hepatitis B and C and human immunodeficiency virus (HIV) [18]. The lesion may also be complicated by bacterial superinfection; even tetanus may be causally linked to tungiasis in areas with low immunization coverage [12, 18]. Tungiasis entails chronic sequelae such as chronic pain, disfigurement and mutilation of the feet and impaired mobility [18]. Thus, it adversely affects quality of life [11] and household economy [18]. It also negatively affects the school attendance and performance of children [11, 18].

In the current study, the prevalence of tungiasis did not differ by gender. Prevalence between the sexes may differ from community to community. Differences in the prevalence of tungiasis between males and females reported in various studies in Africa were not statistically significant [6, 16, 17]. However, a study in Cameroon has demonstrated tungiasis to be more prevalent among males than among females [15].

With regard to actions taken when infested, majority of respondents reported mechanical removal using needle or thorns. This finding is consistent with findings from northeast Brazil and Nigeria [8, 19]. This may imply an attempt to evacuate the jigger flea with locally available materials. However, such materials are often not sterile and may be shared among people and hence may cause bacterial superinfection and serve as a way of transmission of blood-borne infection [18]. This may necessitate the provision of health education to at-risk communities regarding how to manage tungiasis.

In most (about 97%) of the children, the lesions were localized on the feet. This is in agreement with results of studies carried out in a rural population of Northwest Cameroon, Lagos State of Nigeria and northeast Brazil [3, 15, 20]. This might be explained by the fact that the jigger flea is a poor jumper so that most lesions or embedments are confined to the feet instead of ectopic sites [3].

Low level of education of the mother was found to be an important predictor of jigger flea infestation of children. A low educational level, and particularly illiteracy, has been shown to be associated with tungiasis infestation in a previous study as well [7]. This may be related to the low economic status of uneducated or less educated mothers whereby they are unable to fulfill necessities such as shoes for their children.

Domestic animal reservoirs such as pigs, dogs and cats have been frequently identified as important for human tungiasis [21]. Studies done in Nigeria and Kenya have reported domestic reservoir animals to be risk factors for occurrence of tungiasis in a community [1, 6, 22]. The present study showed that the ownership of cats by families was associated with tungiasis infestation. On the other hand, studies in north Brazil and Nigeria have respectively shown that ownership of dogs [7] and pigs [6] are significantly associated with tungiasis. These findings correspond with the thought that in the tropics the human and domestic cycles closely overlap [23].

Failure to wear shoes when walking in soil infested with fleas is the foremost attributing factor for contracting tungiasis. Regular wearing of proper footwear may help in preventing or slowing down the progression of many neglected tropical diseases (NTDs) including tungiasis [6, 24, 25]. In line with this, lack of consistent use of footwear emerged to be a very significant factor associated with occurrence of tungiasis in our study.

The results of the present study should be interpreted considering its limitation. The study kebeles included in the present study were selected purposively for their accessibility. Hence, our sample of children may not be representative of all the children in Wensho district. Kebeles that were not easily accessible may have higher risk of tungiasis. Therefore, their exclusion might have resulted in underestimation of the prevalence of tungiasis.

This study indicated that tungiasis is a common and important public health issue affecting nearly six in ten young children in a rural setting of south Ethiopia. The presence of tungiasis is associated with education status of the mothers, ownership of cat and nonuse or inconsistent use of foot wear by children. Thus, educating heads of households or people about the risk factors, fumigating residential houses, dusting or spraying domestic animals (such as cats) with insecticides and creating awareness on importance of regular use of footwear are needed.