Is the incidence of parasitic lung diseases increasing, and how may this affect modern respiratory medicine?

Lophomonas as a respiratory pathogen-jumping the gun

Human infections with the protozoan Lophomonas have been increasingly reported in the medical literature over the past three decades. Initial reports were based on microscopic identification of the purported pathogen in respiratory specimens. Later, a polymerase chain reaction (PCR) was developed to detect Lophomonas blattarum, following which there has been a significant increase in reports. In this minireview, we thoroughly examine the published reports of Lophomonas infection to evaluate its potential role as a human pathogen. We examined the published images and videos of purported Lophomonas, compared its morphology and motility characteristics with host bronchial ciliated epithelial cells and true L. blattarum derived from cockroaches, analyzed the published PCR that is being used for its diagnosis, and reviewed the clinical data of patients reported in the English and Chinese literature. From our analysis, we conclude that the images and videos from human specimens do not represent true Lophomonas and are predominantly misidentified ciliated epithelial cells. Additionally, we note that there is insufficient clinical evidence to attribute the cases to Lophomonas infection, as the clinical manifestations are non-specific, possibly caused by other infections and comorbidities, and there is no associated tissue pathology attributable to Lophomonas. Finally, our analysis reveals that the published PCR is not specific to Lophomonas and can amplify DNA from commensal trichomonads. Based on this thorough review, we emphasize the need for rigorous scientific scrutiny before a microorganism is acknowledged as a novel human pathogen and discuss the potential harms of misdiagnoses for patient care and scientific literature.

Effective Treatment of Chronic Cough with Tinidazole as the Newest Antiprotozoa against Lophomonas blattarum

Background

Chronic cough is a common problem in the setting of family physicians. Recently, Lophomonas blattarum was considered a cause of respiratory symptoms in children and adults.

Objective

This study is aimed at determining the effect of antiprotozoal treatment of Lophomonas in patients with a chronic cough in Mashhad during 2020-2021.

Materials and Methods

This study was a randomized clinical trial. In this study, 60 patients with chronic cough and unremarkable imaging findings, who were unresponsive to three steps of standard treatment, were randomly assigned to the treatment, with 2 weeks of tinidazole and placebo. The tinidazole and placebo were prepared in a completely identical shape, and a random assignment was performed by a third party. The primary outcome was a complete resolution of cough. A follow-up of treatment was performed. Data were analyzed using the SPSS software version 25.

Results

The basic demographic results showed no significant differences of sex and age between two groups. The results of this study showed a complete resolution of all respiratory symptoms in 40% (12), a complete improvement of cough in 40% (12), and a complete resolution of dyspnea in 50% (10) of the tinidazole group. The remaining showed significant improvement in the severity of cough and dyspnea. Postnasal drip, sputum, body temperature, and airway hyperresponsiveness were improved significantly. After tinidazole treatment, laboratory assessment of bronchial lavage and sputum revealed that 86 percent of smears were converted to negative.

Conclusion

Tinidazole effectively resolved the chronic cough and most of the respiratory symptoms. Lophomonas blattarum is a potential mechanism for chronic cough.

Pulmonary Infection with Lophomonas blattarum

OBJECTIVE

To describe the characteristics of Lophomonas blattarum infection in children based on a retrospective review of medical records data from Beijing Children's Hospital, Capital Medical University, China.

METHODS

This study included 53 cases from July 2014 through December 2016. The data were tabulated and statistically analysed in a Microsoft Excel spreadsheet and SPSS 17.0.

RESULTS

The average age of the 53 patients was 7.10 ± 0.56 years, and the male/female ratio was 3:2.3. The most common clinical manifestation was cough, and almost half of the patients had fever. Furthermore, all patients were treated with metronidazole and recovered.

CONCLUSIONS

For children who have had long-term respiratory symptoms, the possibility of Lophomonas blattarum infection should be ruled out. Metronidazole is effective in treating L. blattarum infection in children.

Authenticity of pulmonary Lophomonas blattarum infection: A case report

Pulmonary protozoal infections are rare. A 28-year-old woman was admitted to hospital with chief complains of cough, sputum, and dyspnea. The clinical laboratory tests for blood revealed an increased eosinophil percentage of 31.3% and significantly elevated total IgE. The chest computed tomography scan revealed that bilateral bronchial walls were thickening, accompanied with patchy spots scattered throughout bilateral lungs. A suspected multiflagellated protozoan was observed under a light microscope. But some different features were observed by electron microscopy, such as the orientation of flagella and nucleus. Besides, both bronchoalveolar lavage fluid and bronchoscopic brush smears underwent Gram staining and Pap staining, which revealed that numerous respiratory ciliated cells were scattered or accumulated in the sample. Finally, she was diagnosed with eosinophil pneumonia. Metronidazole, bronchodilators, and mucolytics were taken for 5 d and symptoms and pulmonary ventilation function improved. We herein report a case of chronic eosinophilic pneumonia, which was misdiagnosed as multiflagellated protozoan infection, and it is suggested that reliable diagnosis approaches are necessary, rather than clinical symptoms and morphological features.

Lophomonas blattarum and bronchopulmonary disease

The natural habitat of the multiflagellate protozoon Lophomonas blattarum is as an endocommensal in the hindgut of insects such as cockroaches. However, it also causes bronchopulmonary disease in humans. The aim of this paper was to review the literature on this organism in the context of respiratory disease. The biology epidemiology, route of transmission, pathogenic mechanisms and diagnosis methods are also described. A total of 61 cases were identified in the literature. The majority of these reports were from China, with some cases from Peru and Spain. Most cases were adult males, although paediatric cases were reported in Peru. Clinical presentation was non-specific, including symptoms such as fever, cough and breathless. Antiprotozoal therapy was generally effective.

Emerging and established parasitic lung infestations

Many lung infestations from established and newly emerging parasites have been reported as a result of the emergence of HIV/AIDS, the increasing use of immunosuppressive drugs, increasing organ transplantations, the increase in global travel, and climate change. A renewed interest in parasitic lung infections has been observed recently because many protozoal and helminthic parasites cause clinically significant lung diseases. The diseases caused by these parasites may mimic common and complicated lung diseases ranging from asymptomatic disease to acute respiratory distress syndrome requiring critical care management. The availability of new molecular diagnostic methods and antiparasitic drugs enables early diagnosis and prompt treatment to avoid the morbidity and mortality associated with these infestations. Good hygiene practices, improvement in socioeconomic conditions, vector control measures, and consumption of hygienically prepared and properly cooked food are essential to reduce the occurrence of parasitic infestations.