Severe lophomoniasis in a patient with diabetes and past history of COVID-19 in Central Iran: case report

Background

Lophomonas blattarum is a type of flagellated protozoan parasite that resides within the hindgut of arthropods such as termites and cockroaches. L. blattarum belongs to the order Hypermastigidia and the suborder Lophomonadia. ¹ This parasite’s cysts can be released into the environment through insect feces and can infect human organs when inhaled as respiratory aerosols. ² L. blattarum has the ability to invade various tissues and organs, including the sinuses, lungs, respiratory tract, and reproductive system, potentially leading to severe complications like the formation of pulmonary cavities.^3,4 Common symptoms of L. blattarum infection include fever, coughing, and excessive mucus production, which can progress to respiratory failure. ⁵ Owing to the similarity of symptoms with other common diseases such as pneumonia and bronchitis, it is challenging to differentiate L. blattarum infection based solely on clinical findings and laboratory tests. ¹ Diagnosis of L. blattarum involves techniques such as examining nasal discharge smears, bronchoscopic brush smears, bronchoscopic biopsy smears, and bronchoalveolar lavage fluid (BALF). ⁶ Imaging studies may reveal features consistent with pneumonia, bronchiectasis, lung abscess, and pleural effusion in cases of lophomoniasis. Because L. blattarum resembles epithelial cells and cannot be easily detected under a light microscope, the parasite is often overlooked (Table 1). However, timely and accurate diagnosis is crucial because the administration of metronidazole is effective in treating this infection. ² Here, we present the case of a patient with respiratory symptoms attributed to long COVID-19. However, further investigation led to suspicion of infection with the protozoan L. blattarum.

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Table 1.

Differences between Lophomonas blattarum and ciliated epithelial cells. ¹

Feature	Lophomonas blattarum	Ciliated epithelial cells
Shape	Pyriform or spherical	Conical or columnar
Flagella/cilia	Flagellar tuft with >50 flagella, unequal length of flagella, irregularly arranged	Ciliary tuft with approximately 200 cilia, uniform length, regularly arranged
Nucleus	Located at the base of the flagellar tuft, both at the anterior end of the cell	Located at the bottom of the cell, opposite to the ciliary tuft, which emerges from the apical face of the cell
Other	The axial filament may be found at posterior end, A marked terminal bar, no terminal bar below the origin of flagella	Absent A marked terminal bar at the apical end of the cell is present just below the origin of cilia

Methods and case presentation

A female patient in her early 60s presented to the emergency department (ED) of Bahar Hospital in Shahroud, a city in Central Iran, on 27 April 2023. The patient experienced severe shortness of breath, tachypnea, and decreased level of consciousness. She had diabetes but had not taken her diabetes medications for a few days. Her vital signs in the ED were normal. Based on the patient’s underlying disease and symptoms, diabetic ketoacidosis (DKA) was suspected. Tests for blood glucose (BG) and venous blood gas (VBG) were requested. The BG and VBG findings (Table 2) all showed metabolic acidosis that confirmed the DKA diagnosis. As a result, the patient underwent treatment for DKA. The signs and symptoms of DKA resolved after 2 days of hospitalization, although she still had shortness of breath. Given the patient's reported history of COVID-19 symptoms 2 months prior, it was assumed that the current shortness of breath and phlegm production were caused by the earlier COVID-19 infection. She also stated that she had previously had symptoms resembling an asthma attack. A COVID-19 reverse-transcription polymerase chain reaction test was ordered, and the result was negative. Chest computed tomography scan revealed pleural effusion in both lungs, atelectasis in the superior lobe of the left lung, consolidation in the middle lobe of the right lung, calcified mediastinal lymph nodes, and cardiomegaly. Bronchoscopy was done after consulting with a pulmonology specialist. A BALF sample was sent to the laboratory of Bahar Hospital. A viable flagellated protozoan (Figure 1; video presented in the supplementary material), the specific identity of which could not be determined, was observed under light microscopy. Subsequently, a BALF sample was sent (at ambient temperature, 28°C–32°C) to the Iranian National Registry Center for Lophomoniasis (INRCL) in northern Iran for additional analysis. Examination confirmed the presence of the L. blattarum parasite with severe infection intensity (>5 parasites per 100 microscopic fields), according to the grading classification of Fakhar et al. ⁶ A conventional PCR test was also performed for further confirmation of L. blattarum, which was positive. ⁷ The patient was given metronidazole (1.5 g/day) intravenously for 10 days. Her respiratory symptoms completely resolved, and her laboratory test results were normal at the subsequent follow-up appointment.

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Table 2.

Laboratory data results for the patient in the emergency department.

Lab data parameter	Result	Reference range
pH a	7.21	7.35–7.45
PCO2	33 mmHg	35–45 mmHg
HCO3	16 mmol/L	22–28 mEq/L
Blood glucose	570 mg/dL	–
WBC	18,100 U/L	4000–1000 cells/mm3
RBC	3.93 × 106	4.2–5.4 cells/mcL
HB	11 g/dL	14–18 g/dL
PLT	155,000 cells/mm3	145,000 to 450,000 cells/mm3
HCT	30	35.5%–44.9%
Neutrophils	86%	55%–70%
Lymphocytes	11%	20%–35%
Monocytes	3%	3%–8%
CRP	81 mg/L	<6 mg/L
ESR	126 mm/hour	0–20 mm/hour
Urea	17 mg/dL	13–40 mg/dL
Cr	0.46 mg/dL	0.5–1.3 mg/dL

a

Results for pH, PCO₂, and HCO₃ were obtained from venous blood gas and not arterial blood gas.

PCO₂, partial pressure of carbon dioxide; HCO₃, bicarbonate; WBC, white blood cells; RBC, red blood cells; HB, hemoglobin; PLT, platelet count; HCT, hematocrit; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; Cr, creatinine.

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Figure 1.

Lophomonas blattarum under the light microscope. (a) Epithelial cell (EPI) and L. blattarum (L.b) are shown and (b) unstained wet smear.

The reporting of this study conforms to the CARE guidelines. ⁸ We obtained the patient’s consent prior to treatment.

Discussion

The present case highlights the diagnostic challenges and clinical implications of severe lophomoniasis in a patient initially suspected of experiencing long COVID symptoms. L. blattarum is a flagellated protozoan primarily found in the hindgut of arthropods. Although this parasite primarily infects insects, it can cause human infections when inhaled as respiratory aerosols derived from insect feces. L. blattarum infections are characterized by a wide range of symptoms and potential complications. The parasite has the ability to invade various tissues and organs, leading to respiratory symptoms such as fever, coughing, and excessive mucus production. In severe cases, respiratory failure can occur. However, owing to the similarity of symptoms with other respiratory conditions, diagnosis based solely on clinical findings can be challenging. ¹ The main countries reporting cases of L. blattarum infection include China, Iran, and India. ¹

In our case, the diagnosis of L. blattarum was established through bronchoscopy and subsequent analysis of BALF at the INRCL. Identification of the mobile flagellated protozoan under light microscopy confirmed the presence of L. blattarum. An intriguing aspect of this case is that the BALF sample was sent from Shahroud to Mazandaran, which took nearly 4 days; nevertheless, the organism remained viable during these 4 days, in which the average temperature was 30°C. This made the diagnosis considerably easier because epithelial cells were lost over this length of time. It should be noted that a PCR test for L. blattarum was done for further confirmation. ⁷

The importance of this case lies in the recognition of L. blattarum as a potential cause of respiratory symptoms, even in patients with a previous history of COVID-19 infection. The coexistence of respiratory symptoms attributed to long COVID and an underlying L. blattarum infection emphasizes the importance of considering alternative diagnoses and conducting further investigation, especially in cases where symptoms persist or worsen despite previous treatments. ⁹ L. blattarum has been observed in pericardial fluid. ¹⁰ Although our patient did not undergo a thoracentesis for the analysis of pleural fluid, it is possible that her pleural effusion was caused by L. blattarum.

This case highlights the need for increased awareness and understanding of L. blattarum infections among healthcare professionals. Improved knowledge regarding this parasitic infection can lead to prompt and accurate diagnoses and facilitate appropriate treatment interventions. It is also essential to educate the public about preventive measures, such as maintaining proper hygiene and minimizing exposure to environments with high arthropod populations.

In conclusion, this case report underscores the diagnostic challenges and clinical implications associated with L. blattarum infection, serving as a reminder to consider alternative etiologies for respiratory symptoms, even in individuals with a history of COVID-19 infection. By raising awareness and improving diagnostic capabilities, healthcare professionals can enhance the identification and management of L. blattarum infections, ultimately improving patient outcomes.

Supplemental Material

Supplemental Material