Francesca Tamarozzi

Onchocerciasis: the Role of Wolbachia Bacterial Endosymbionts in Parasite Biology, Disease Pathogenesis, and Treatment

SUMMARY The discovery of Wolbachia intracellular bacteria within filarial nematodes, including Onchocerca volvulus, the causative agent of onchocerciasis or “river blindness,” has delivered a paradigm shift in our understanding of the parasites biology, to where we now know that the bacterial endosymbionts are essential for normal development of larvae and embryos and may support the long-term survival of adult worms. The apparent mutualistic dependency has also offered a novel approach to the treatment of onchocerciasis through the use of antibiotics to eliminate Wolbachia, delivering for the first time a treatment which has significant macrofilaricidal efficacy. Studies with other filarial nematode species have also highlighted a role for Wolbachia in transmission and infection of the mammalian host through a fascinating manipulation of mast cell-mediated vasodilation to enhance infectivity of vector-borne larvae. Wolbachia has also been identified as the principal driver of innate and adaptive Th1 inflammatory immunity, which can either contribute to disease pathogenesis or, with the Wolbachia-mediated recruitment of mast cells, enhance infectivity. The Wolbachia activation of innate inflammation also drives inflammatory adverse events in response to chemotherapy with either diethylcarbamazine (DEC) or ivermectin. In this review we summarize the experimental and field trial data which have uncovered the importance of Wolbachia symbiosis in onchocerciasis.

Justified concern or exaggerated fear : the risk of anaphylaxis in percutaneous treatment of cystic echinococcosis - a systematic literature review

Percutaneous treatment (PT) emerged in the mid-1980s as an alternative to surgery for selected cases of abdominal cystic echinococcosis (CE). Despite its efficacy and widespread use, the puncture of echinococcal cysts is still far from being universally accepted. One of the main reasons for this reluctance is the perceived risk of anaphylaxis linked to PTs. To quantify the risk of anaphylactic reactions and lethal anaphylaxis with PT, we systematically searched MEDLINE for publications on PT of CE and reviewed the PT-related complications. After including 124 publications published between 1980 and 2010, we collected a total number of 5943 PT procedures on 5517 hepatic and non-hepatic echinococcal cysts. Overall, two cases of lethal anaphylaxis and 99 reversible anaphylactic reactions were reported. Lethal anaphylaxis occurred in 0.03% of PT procedures, corresponding to 0.04% of treated cysts, while reversible allergic reactions complicated 1.7% of PTs, corresponding to 1.8% of treated echinococcal cysts. Analysis of the literature shows that lethal anaphylaxis related to percutaneous treatment of CE is an extremely rare event and is observed no more frequently than drug-related anaphylactic side effects.

Long term impact of large scale community-directed delivery of doxycycline for the treatment of onchocerciasis

BackgroundAnti-Wolbachia treatment with doxycycline is effective in sterilising and killing adult Onchocerca volvulus nematodes, proving superior to ivermectin and of great potential as an alternative approach for the treatment and control of onchocerciasis, particularly in areas of Loa loa co-endemicity. Nevertheless, the length of the required treatment poses potential logistical problems and risk of poor compliance, raising a barrier to the use of doxycycline in Mass Drug Administration (MDA) strategies. In 2007 and 2008 a feasibility trial of community-directed treatment with doxycycline was carried out in two health districts in Cameroon, co-endemic for O. volvulus and L. loa. With 17,519 eligible subjects, the therapeutic coverage was 73.8% with 97.5% compliance, encouraging the feasibility of using doxycycline community-directed delivery in restricted populations of this size. The current study evaluated the effectiveness of this community-directed delivery of doxycycline four years after delivery.FindingsInfection with O. volvulus was evaluated by skin biopsy and nodule palpation. Of the 507 subjects recruited, 375 had completed the treatment with doxycycline followed by one or two rounds of annual ivermectin MDA and 132 received one or two rounds of annual ivermectin MDA alone. Statistically significant lower microfilarial prevalence (17.0% [doxycycline plus ivermectin group], 27.0% [ivermectin only group], p = 0.014) and load (p = 0.012) were found in people that had received doxycycline followed by ivermectin compared to those who received ivermectin only.ConclusionsThis study demonstrates the long-term effectiveness of doxycycline treatment delivered with a community-directed strategy even when evaluated four years after delivery in an area of ongoing transmission. This finding shows that a multi-week course of treatment is not a barrier to community-delivery of MDA in restricted populations of this size and supports its implementation to compliment existing control strategies for onchocerciasis, where needed.

Efficacy and Safety of PAIR for Cystic Echinococcosis: Experience on a Large Series of Patients from Bulgaria

We report our experience with puncture, aspiration, injection, and reaspiration (PAIR) for the treatment of cystic echinococcosis in Bulgaria. PAIR was performed in 230 patients with 348 echinococcal cysts. At 12-month follow-up, 77.6% of the cysts, all cystic echinococcosis (CE) 1 and CE3a cysts according to the World Health Organization Informal Working Group classification, showed various degrees of obliteration. In 11.5% of cysts, all of which were > 10 cm-type CE1, a significant amount of fluid persisted, and they were punctured again. Of those, 16 (4.6%) contained protoscolices and were treated by a second PAIR. The remaining 24 (6.9%) cysts were treated by simple aspiration or drainage. No significant reduction in size and no changes in the structure were observed in 10.9% of cysts, all of which were classified as CE2 or CE3b. Complications developed in 25.2% of patients, including severe anaphylactic reaction in two (0.9%) patients. Our experience confirms that PAIR is a successful first-choice treatment when a stage-specific approach is taken.

Acceptance of standardized ultrasound classification, use of albendazole, and long-term follow-up in clinical management of cystic echinococcosis: a systematic review.

Purpose of review Cystic echinococcosis is a chronic, complex, and neglected disease. The need for a simple classification of cyst morphology that would provide an accepted framework for scientific and clinical work on cystic echinococcosis has been addressed by two documents issued by the WHO Informal Working Group on Echinococcosis in 2003 (cyst classification) and in 2010 (Expert consensus for the diagnosis and treatment of echinococcosis). Recent findings Here we evaluate the use of the WHO Informal Working Group on Echinococcosis classification of hepatic cystic echinococcosis, the acceptance by clinicians of recommendations regarding the use of albendazole, and the implementation of the long-term follow-up of patients with hepatic cystic echinococcosis in the scientific literature since the WHO Informal Working Group on Echinococcosis recommendations were issued. Summary Of the publications included in our review, 71.2% did not indicate any classification, whereas 14% used the WHO Informal Working Group on Echinococcosis classification. Seventy-four percent reported the administration of peri-interventional albendazole, although less than half reported its modality, and 51% the length of patient follow-up. A joint effort is needed from the scientific community to encourage the acceptance and implementation of these three key issues in the clinical management of cystic echinococcosis.

Long-term Sonographic and Serological Follow-up of Inactive Echinococcal Cysts of the Liver: Hints for a “Watch-and-Wait” Approach

Human cystic echinococcosis is a chronic, complex and neglected infection. Its clinical management has evolved over decades without adequate evaluation of efficacy. Recent expert opinion recommends that uncomplicated inactive cysts of the liver should be left untreated and solely monitored over time (“watch-and-wait” approach). However, clinical data supporting this approach are still scant and published mostly as conference proceedings. In this study, we report our experience with long-term sonographic and serological follow-up of inactive cysts of the liver. From March 1994 to October 2013, 38 patients with 47 liver cysts, diagnosed as inactive without any previous treatment history, were followed with ultrasound and serology at 6–12 months intervals for a period of at least 24 months (median follow-up 51.95 months) in our outpatient clinic. In 97.4% of patients, the cysts remained inactive over time and in only one case was reactivation of the cyst detected. No complications occurred during the time of monitoring. During follow-up, serology tests for CE were negative at diagnosis or became negative in 74.1% and were positive or became positive in 25.9% of cases. Patients with inactive cysts on ultrasound but positive serological tests were also investigated by CT scan (chest and abdomen) to rule out extra-hepatic cyst localization. This study confirms the importance of a stage-specific approach to the management of cystic echinococcosis and supports the use of a monitoring-only approach to inactive, uncomplicated cysts of the liver. It also confirms that serology plays only an ancillary role in the clinical management of these patients, compared to ultrasound and other imaging techniques. The implications of these findings for clinical management and natural history of cystic echinococcosis are discussed.

The Italian registry of cystic echinococcosis (RIEC): the first prospective registry with a European future

Cystic echinococcosis (CE), a worldwide zoonosis, is highly endemic in southern and eastern Europe. Its actual prevalence is unknown due to the lack of efficient reporting systems designed to take into account the particular features of the disease. Neglect of CE makes diagnosis and clinical management difficult outside referral centres, with inconsistencies in clinical practice and often unnecessary procedures carried out that have associated risks and costs. The Italian registry of CE (RIEC) is a prospective multicentre registry of CE patients seen from January 2012 in Italian health centres; data are voluntarily submitted to the registry. Its aims are to show the prevalence of CE in Italy, bring the importance of this infection to the attention of health authorities, encourage public health policies towards its control, and stimulate biological, epidemiological and clinical research on CE. From January 2012 to February 2014, a total 346 patients were enrolled in 11 centres, outnumbering national reports of many CE-endemic European countries. We discuss preliminary data and challenges of the RIEC, template for the European registry of CE, which has been implemented within the Seventh Framework Programme project HERACLES (Human cystic Echinococcosis ReseArch in CentraL and Eastern Societies) since September 2014.

Spinal cystic echinococcosis - a systematic analysis and review of the literature : part 2. treatment, follow-up and outcome

Bone involvement in human cystic echinococcosis (CE) is rare, but affects the spine in approximately 50% of cases. Despite significant advances in diagnostic imaging techniques, surgical treatment and introduction of pharmacological therapy, spinal echinococcosis remains associated with a high degree of morbidity, disability and mortality. We systematically reviewed the published literature of the last five decades to update and summarize the currently existing data on treatment, follow-up and outcome of spinal CE.

Factors influencing the serological response in hepatic echinococcus granulosus infection

Knowledge of variables influencing serology is crucial to evaluate serology results for the diagnosis and clinical management of cystic echinococcosis (CE). We analyzed retrospectively a cohort of patients with hepatic CE followed in our clinic in 2000-2012 to evaluate the influence of several variables on the results of commercial enzyme-linked immunosorbent assay (ELISA) and indirect hemagglutination (IHA) tests. Sera from 171 patients with ≥ 1 hepatic CE cyst, and 90 patients with nonparasitic cysts were analyzed. CE cysts were staged according to the WHO-IWGE classification and grouped by activity. A significant difference in ELISA optical density (OD) values and percentage of positivity was found among CE activity groups and with controls (P < 0.001). The serological response was also influenced by age (P < 0.001) and cyst number (P = 0.003). OD values and cyst size were positively correlated in active cysts (P = 0.001). IHA test showed comparable results. When we analyzed the results of 151 patients followed over time, we found that serology results were significantly influenced by cyst activity, size, number, and treatment ≤ 12 months before serum collection. In conclusion, serological responses as assessed by commercial tests depend on CE cyst activity, size and number, and time from treatment. Clinical studies and clinicians in their practice should take this into account.

Spinal cystic echinococcosis--a systematic analysis and review of the literature: part 1. Epidemiology and anatomy.

Bone involvement in human cystic echinococcosis (CE) is rare, but affects the spine in approximately 50% of cases. Despite significant advances in diagnostic imaging techniques as well as surgical and medical treatment of spinal CE, our basic understanding of the parasites predilection for the spine remains incomplete. To fill this gap, we systematically reviewed the published literature of the last five decades to summarize and analyze the currently existing data on epidemiological and anatomical aspects of spinal CE.