Trachoma

Trachoma is an ocular bacterial infection that results in inflammation of the conjunctiva, “active trachoma.” Repeated bouts of active trachoma can scar the inner eyelid, which often leads to trichiasis—an inward turning of 1 or more eyelashes, damaging the cornea [6]. This is an extremely painful condition that will lead to irreversible blindness if not surgically corrected in a timely manner. There are over 200 million people living in areas with a high risk of trachoma-related blindness [6]. The recommended procedure for trichiasis is known as bilamellar tarsal rotation (BLTR) surgery [6]. BLTR surgery carries a relatively small estimated cost of US$40 and remains a cost-effective intervention against vision loss [7].

Unlike with most other NTDs, surgical interventions in trachoma have been an integral part of the framework, supported by the World Health Organization (WHO) Alliance for Global Elimination of Blinding Trachoma by the year 2020 (GET 2020) [6]. They have been implemented globally as SAFE: surgery for trachomatous trichiasis (TT); antibiotic treatment to clear ocular infection; facial cleanliness to reduce the transmission of ocular Chlamydia trachomatis; and environmental improvement, particularly access to water and sanitation [6].

A recent achievement toward the goal of elimination was the Global Trachoma Mapping Project (GTMP), which has identified 100 million additional individuals living in areas previously known as “suspected endemic” that will require health interventions [5]. As shown by this project, the proper identification of areas that require intervention is a prerequisite for the achievement of the true elimination of any NTD [5]. In 2012, 169,121 people received trichiasis surgery, and in 2013, that number increased to 234,000 [6]. However, there is currently an estimated backlog of 5 million cases of trichiasis surgery [8]. Thus, the current level of productivity is not adequate to reach the GET 2020 targets, and there is a clear need to scale up trichiasis surgery services globally [9].

LF

LF is a vector-borne parasitic disease that arises from the infection of lymphatic vessels with adult filarial worms, eventually leading to chronic disabling sequelae, including hydrocele, lymphedema, and elephantiasis [10]. Of these, hydrocele is curable through surgery (hydrocelectomy), while lymphedema and elephantiasis can be managed with nonsurgical techniques, such as improved hygiene and skin care [11]. MDA treatments function to decrease the prevalence of infection by lowering the concentration of microfilariae in the blood to a point at which transmission is no longer possible [10, 11]. Thus, MDA is a major tool in the global elimination of LF, but it does not significantly address hydroceles requiring surgical interventions or lymphedema and elephantiasis morbidities that would be addressed through improved hygiene, compression, and antibiotics.

Over the past 15 years (2000–2015), since the inception of the Global Programme to Eliminate Lymphatic Filariasis (GPELF), more than 97 million estimated cases of LF have been prevented or cured predominantly through MDA [10]. However, as many as 36 million hydrocele and lymphedema cases remain [10]. More recent Global Burden of Disease Study 2015 estimates show that, for the 38.46 million people living with LF, approximately 19.71 million show evidence of detectable microfilariae, while 18.76 million exhibit complications that could require surgical intervention (Table 1) [12].

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Table 1. Global morbidities due to LF and trachoma (from the GBD 2015 [12]).

https://doi.org/10.1371/journal.pntd.0005563.t001

For the GPELF to reach its goal, patient care—as achieved through the implementation of morbidity management and surgery—is needed in conjunction with MDA, given that there are a large number of people with existing severe disease for whom MDA would prove too late to be effective [8]. Preventing the further progression of disease in these patients requires morbidity management and disability prevention (MMDP) services. Surgery is an essential part of MMDP, as seen in the minimum package of recommended care suggested by WHO for the care of patients with LF-related chronic disease. The minimum package includes hydrocelectomy, treatment for adenolymphangitis (ADL), and lymphedema management in order to prevent ADL episodes and subsequent disease progression [10]. Hydrocele surgery is estimated at US$80–US$360, and the cost of procedures for lymphedema prevention and management is even smaller [7].

In addition to the health burden, people suffering from chronic LF complications could incur losses of up to 30% in productivity, translating to the economic loss of hundreds of millions of dollars each year [13,14,15]. Thus, MMDP must be implemented in conjunction with MDA to achieve the elimination of LF as a health and economic burden, and surgical care is a crucial part of this effort.

Trachoma

In order to increase productivity and clear the existing backlog in trichiasis surgery cases, a significant scale-up and refocusing of surgical services will be necessary. Specifically, with regards to the backlog, it may be necessary to institute urgent responses that address a large number of cases at one time (campaign-style approach) [9]. In addition, matching resource allocation will be required, and a refocusing of surgical resources to areas where patients are most concentrated would serve to improve productivity. Some of the barriers to low uptake that have been identified are lack of awareness, direct and indirect costs, and distance to services [9]. Thus, local promotion strategies, such as using village leaders to encourage patients to seek care at health facilities, have been proposed as strategies to increase surgical access [9]. Other studies have also observed that a recurrence of trichiasis following surgery is relatively common and has been frequently tied to surgeon skill [16]. Proper standardization and supervision of procedures could reduce adverse outcomes and improve surgeon skill. Additionally, 1 dose of azithromycin given postoperatively has been shown to yield a 30% reduction in recurrence in Ethiopia [17].

LF

Many of the strategies in the surgical framework utilized for trachoma elimination efforts can be reasonably extrapolated to expand surgical coverage for hydrocele repair. For example, the mapping of LF, and specifically hydrocele, prevalence in subregions within endemic areas by using rapid antigen testing, along with mobile technology (as seen in GTMP), could prove useful in identifying local regions in need of access to surgical care [8]. The involvement of members at the rural level who can help identify and promote individuals to seek proper surgical care in a timely manner could also aid in surgical uptake [9]. Additionally, as shown in a recent study in Malawi, better characterization of regional surgical output and access within endemic countries and geographical distribution of hydrocele patients in relation to the servicing facility could improve the monitoring of progress and guide future scale-up of services [18].

Currently, of the 73 LF-endemic countries, only 41 (56%) have reported lymphedema cases, and 38 (52%) have done so for hydrocele cases [10]. Of those, 35 countries (48%) reportedly provided MMDP services, but only a mere 18 countries (25%) have shown evidence of the surveillance of MMDP at the level of the implementation unit [10]. Six of the 18 endemic countries conducting surveillance have thus far been assessed and formally acknowledged as having achieved elimination [10]. However, the goal, as set by WHO, is for 100% of endemic countries to enter postintervention surveillance by 2020 [10]. Needless to say, this will require a large scale-up and expansion of surgical care, along with other MMDP services.