Detection of a Lophomonas, a rare pathogen in Bronchoalveolar lavage : Tropical Parasitology

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Detection of a Lophomonas, a rare pathogen in Bronchoalveolar lavage

Keche, Archana; Khatoon, Shagufta; Sahu, Dibakar1

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Tropical Parasitology 12(2):p 124-126, Jul–Dec 2022. | DOI: 10.4103/tp.tp_97_21
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Lophomonas infection is an emerging parasitic disease-causing respiratory infection. Although common in immunocompromised patient, it has been observed also in some immunocompetent cases. We report the case of a 45-year-old male who presented with productive cough, fever, and chest pain, with marked eosinophilia and cavitary lesion in the X-ray chest. KOH preparation and acid-fast bacilli microscopy of bronchoalveolar lavage (BAL) were negative. Direct microscopic examination of BAL accidentally showed a large number of living Lophomonas species with the movement of flagella. Methylene blue and Giemsa staining showed the plume of flagella and the nucleus. The patient was managed conservatively with metronidazole and get cured. It was concluded that the patient presented with signs and symptoms of pneumonia must be evaluated for rare events also if the patient was not responding with typical management of pneumonia. We reported the first case of this rare entity in Chhattisgarh state in an immunocompetent young Indian male.


Lophomonas blattarum (L. blattarum) is a protozoan parasite living in the intestinal tracts of termites, and cockroaches rarely cause bronchopulmonary lophomoniasis (BPL) with nonspecific symptoms. Chen and Meng from China reported the first case of pulmonary L. blattarum infection in 1993. About 137 cases have only been reported in the literature between 1993 and 2013.[1] Since Lophomonas cannot be cultured, their microscopic identification is based on the fresh and stained samples evaluation of sputum, bronchoalveolar lavage (BAL), and bronchial aspirate. To avoid identification errors, it is recommended to analyze the stained samples, mainly using Papanicolaou, Giemsa, or trichrome staining.[23] We report here the first case of accidental detection of Lophomonas in a young male patient who presented with productive cough, fever, and chest pain without a history of tuberculosis, COVID-19 infection, and chronic obstructive pulomonary disease (COPD) at a tertiary care institution in Chhattisgarh, India.


A 45-year-old male presented with a complaint of productive cough, fever for 1 week, and chest pain. There was no history of tuberculosis, COVID-19 infection, bronchial asthma, human immunodeficiency virus (HIV), COPD, diabetes mellitus, and hypertension. On clinical examination, multiple rashes over the hand and abdomen were present. Routine laboratory tests revealed eosinophilia. A sputum smear for acid-fast bacilli (AFB) was negative. Sputum culture did not grow any organism. Viral markers including HIV, hepatitis B virus surface antigen, and hepatitis C antibody (anti-HCV) test were negative. KOH preparation and AFB microscopy of BAL were negative. Examination of the wet mount of BAL revealed actively motile flagellates with a polar tuft of flagella lashing rhythmically identified as L. Blattarum [Figure 1b and]. Methylene blue showed the plume of flagella and the nucleus [Figure 1a]. X-ray of the chest shows a cavitary lesion in the left lung and noncontrast computed tomography reveals the area of subsegmental consolidation, septal thickening, and ground-glass opacity. A large cavity 5 cm × 6 cm in the left lobe with mild left pleural effusion [Figure 1c]. Oral metronidazole 400 mg thrice daily was advised for 2 weeks. It was concluded that the patient presented with signs and symptoms of pneumonia must be evaluated for rare events also if the patient was not responding with typical management of pneumonia. We reported the first case of this rare entity in Chhattisgarh state in an immunocompetent young Indian male.

Figure 1:
(a) Lophomonas in methylene blue with bunch of flagella (b) Lophomonas in wet mount (c) X-ray chest showing cavitary lesion in the lung

Ethical consideration

Written informed consent was obtained from the patient and assured to maintain confidentiality.


Pulmonary infection among human beings is rare with L. blattarum.[4] One case of a patient having dual infection with tuberculosis has been reported from India.[5] Although Lophomonas infestation is common in immunocompromised, such as with hematopoietic transplantation, leukemia, patients with sinusitis, asthma and tuberculosis, its known to be also in immunocompetent cases. A similar observation has been noted in another case report, where 70% were on immunosuppression, 30% post-transplant, and patients with acute myeloid leukemia.[6] Unlike other studies, in the present study, the patient was immunocompetent and had features of pulmonary infection and marked blood eosinophilia. A similar finding was observed in another study having significant eosinophilia.[1] In another study, symptoms are similar to the conditions such as bronchial asthma, pneumonia, bronchiectasis, or lung abscesses, and there is almost always coughing like present study.[6] L. blattarum can be detected in sputum smears, BAL, or biopsy smears.[7] In our case, although the sputum smears were negative, the infection was confirmed on BAL. A similar finding was observed in another study where sputum smears were negative, but the infection was confirmed on BAL.[1] To date, several studies have focused on L. blattarum infection, and rare cases of BPL are becoming more frequent. Faktar et al. detected the flagellate protozoa morphologically identified as Lophomonas in a direct wet mount of nasal discharge which was confirmed by PCR.[8] Coinfection of L. blattarum and COVID-19 was also reported by Nakhaei et al., while the present case had no history of COVID-19 infection.[9]


Rare cases need to be documented to understand the pathogenicity and incidence of the unusual pathogen such as Lophomonas, of which very sparse cases have been reported, which will help in improving diagnostic methods and promoting preventive measures against the parasite that causes BPL.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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Bronchopulmonary protozoal infection; eosinophilia; immunocompetent; Lophomonas

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