Introduction

Tungiasis is a parasitic skin infection caused by female Tunga penetrans or jigger fleas. It is a significant public health problem in tropical and subtropical regions, especially in rural areas of Africa, Latin America, and other southern regions.^1,2

Painful, itchy lesions caused by the condition may not get treated and, in severe cases, can lead to serious complications. This condition is exacerbated in settings characterised by poverty, poor sanitation, and limited access to healthcare. 

Tunga penetrans has a 6-stage life cycle. The female typically embeds itself in the skin on the feet, although other areas can also be affected.^2,3 The more serious complications result from a lesion infected with secondary bacterial pathogens. If they are not treated in time, these infections can become chronic and cause long-term morbidity. 

Tungiasis is not only a dermatological problem but also a social and economic problem. Secondary bacterial infections, including cellulitis and abscesses, can prolong the illness and increase the risk of severe outcomes.

Pathophysiology of tungiasis

The life cycle of Tunga penetrans starts when the female flea burrows into the skin, typically on the feet, and feeds on blood while laying eggs. This causes the flea's body to swell and leads to massive tissue damage by forming the characteristic lesions associated with tungiasis.³ Larvae are released into the environment from the flea, which remains embedded in the skin, ending the lifecycle. 

To penetrate the epidermis, the flea injects its sharp mouthparts through the skin. This feeding process results in redness, swelling, and pain at the affected site.^2,3 Despite the host's immune response, the flea's position in the skin makes it difficult for the body to eliminate. Inflammatory cells, including neutrophils and macrophages, are recruited to the site, causing swelling and discomfort. The immune response may inadvertently create conditions that favour secondary bacterial infections.³ 

These bacterial infections are more likely to occur in individuals with poor higiene is poor hygiene, weakened immune systems, or when lesions are left untreated.³ Complications, including cellulitis or abscess, will be more common if there is continued flea presence on the lesion or trauma to the lesion.

Common secondary bacterial infections

Complications of tungiasis include secondary bacterial infections.  One of the frequently observed complications is cellulitis, characterised by redness, swelling, warmth, and pain at the lesion site.^3,4 This condition arises when bacteria such as Streptococcus or Staphylococcus aureus invade the damaged skin. 

If not treated effectively,  cellulitis can rapidly worsen, spreading to other parts of the body and leading to systemic symptoms such as fever. In some cases, the infection progresses, forming pus in the tissue, causing local swelling, pain, and fluctuance.⁴  This condition is usually treated by draining the pus-filled pocket, followed by antibiotics to prevent further tissue damage. 

If the infection spreads to the lymphatic vessels, it may lead to lymphangitis, identified by red streaks radiating from the lesion, along with fever. In more severe cases, bacteria may enter the bloodstream, causing bacteremia or septicemia, which can lead to systemic complications such as shock, organ failure, and even death.^3-5 

Another severe complication is osteomyelitis, a bone infection caused by the spread of bacteria to underlying bone tissue. This condition results in pain, fever, and substantial bone damage. Osteomyelitis requires aggressive treatment, including long-term antibiotics and sometimes even surgery.  

Tunga penetrans infection can also cause Clostridium tetani wound infection, resulting in muscle spasms and rigidity, a potentially fatal effect requiring immediate emergency medical care.

Bacterial pathogens involved

Complications with bacterial pathogens are regularly seen with tungiasis infection. The most common bacterium involved is Staphylococcus aureus, which may cause abscesses, cellulitis, or other skin infections. Another leading pathogen is Streptococcus pyogenes, which causes cellulitis and lymphangitis.⁶ In association with delayed healing and additional tissue damage, Pseudomonas aeruginosa is frequently responsible for chronic wound infections, particularly in individuals with longstanding and untreated tungiasis lesions. Open wounds carry a greater risk for Clostridium tetani infection, which causes tetanus, leading to muscle rigidity and spasms.^6,7 Moreover, Escherichia coli and Klebsiella pneumoniae can act as opportunistic bacteria that complicate tungiasis infections in people with weakened immune systems or poor hygiene.

Risk factors for secondary infections

Several factors increase the susceptibility to secondary infections in cases of tungiasis.. Poor hygiene and lack of clean water significantly contribute to bacterial entry and colonisation at the infestation site. ^3,5,8 Even after the flea is removed, the lesion can remain vulnerable to infection. 

Conditions such as malnutrition, diabetes, and other immune-compromising diseases further weaken the body's ability to mount an effective immune response, increasing the risk of infection.⁸ 

Environmental factors also play a critical role. Warm and humid climates promote bacterial growth.  Additionally, in endemic regions, contaminated soil often harbours Tunga penetrans and additional pathogens, serving as a continuous source of reinfection and further complicating the risk of secondary infections.

Diagnosis and clinical presentation

Diagnosis of tungiasis secondary bacterial infections is based on a physical examination of the lesions. That includes skin swelling, pus drainage, redness, or fever.⁷ Some methods of diagnosing secondary infection include evaluating the appearance of the lesion and reviewing the patient's history of tungiasis. Bacterial cultures can confirm the presence of the specific pathogen in the laboratory and may reveal systemic infection through an elevated blood white blood cell (WBC) count.^2,5 Imaging studies, such as X-rays or ultrasound, are used in more severe cases when deep tissue involvement, to detect complications such as osteomyelitis or abscess formation. Based on these findings, appropriate treatment decisions are made.

Treatment and management

Cleaning or disinfecting the lesion is necessary to avoid further bacterial colonisation. Thus, wound care and hygiene are essential. For mild cases, topical antibiotics are used, while systemic antibiotics are prescribed for more severe or deep infections.^1,3 Safe flea removal and surgical debridement of infected tissue are required for deep-embedded fleas to reduce the risk of further infection. Analgesics and anti-inflammatory medications are also used to provide patient comfort and manage pain associated with the lesions. Vaccination against tetanus, particularly in endemic regions, is of utmost importance in providing prophylaxis in cases where wounds are at risk of Clostridium tetani infection.^6-8 Factors contributing to the reduction of complications and improvement in patient outcomes include timely intervention and proper care.

Prevention strategies

Prevention of tungiasis requires a multi-faceted approach. Wearing protective shoes in areas where Tunga penetrans is endemic is one of the most effective ways to reduce exposure to the disease. It is also important to improve sanitation and hygiene practices to minimise the risk of having contact with contaminated soil and reduce the likelihood of flea infestation.³ Community education and health promotion efforts can help raise awareness about the risk of tungiasis, the importance of recognising its symptoms, and the need for early treatment and intervention.

In addition, vector control measures such as the use of pesticides and environmental management (e.g. proper sewage disposal and habitat modification) can reduce the presence of Tunga penetrans in affected communities.^4,7 Combined, these strategies can have an important impact on lowering the incidence of  tungiasis and its associated complications

Frequently asked questions (FAQs)

What is tungiasis, and how is it transmitted?

Tungiasis is a parasitic skin infection caused by Tunga penetrans, transmitted through contact with contaminated soil.

Why do secondary bacterial infections occur in tungiasis?

Secondary infections occur when bacteria enter through the lesion caused by the embedded flea.

How can I tell if a tungiasis lesion is infected?

Signs include redness, swelling, pus, and fever.

What antibiotics are used to treat bacterial infections in tungiasis?

Topical or systemic antibiotics may be used,  depending on the severity of the infection.

Can tungiasis lead to life-threatening complications?

Yes. If left untreated, tungiasis can lead to complications such as sepsis or tetanus.

How can I prevent tungiasis in endemic areas?

Wearing protective footwear, maintaining good hygiene, and promoting community education are key prevention strategies.

Is tungiasis a neglected tropical disease?

Yes, it is recognised as a neglected tropical disease in endemic regions.

Summary

Tungiasis is a parasitic disease (caused by Tunga penetrans) that can cause painful lesions associated with secondary bacterial infections. If left untreated, it can lead to cellulitis, septicemia, and osteomyelitis, and an early diagnosis and treatment are required. Good hygiene, wearing protective footwear, and community education are key measures for preventing tungiasis and its associated infections. Public health interventions and awareness interventions in endemic areas can help reduce the disease burden. Further research is still needed to further understand its pathophysiology and to develop control strategies that improve health outcomes in affected communities.