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At 16∶18 on August 8, 2021, a hospital in Beijing Municipality reported a suspected case of inhalational anthrax. Six hours later, Beijing CDC reported that pleural effusion sample of the case tested positive for nucleic acids of Bacillus anthracis using fluorescent real-time polymerase chain reaction (PCR). On August 13, 1 strain of B. anthracis was isolated from dead cattle in the patient’s village. On August 19 and 20, 2 samples of pleural effusion collected from the patient with 24-hour interval were negative for B. anthracis both by real-time PCR and bacterial culture. This met the requirements for discharging anthrax cases from hospital isolation. A total of 127 close contacts of the case in Beijing were quarantined at designated sites or at home for 12 days from the last contact with the patient.
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The patient was a 46-year-old female from Weichang Manchu and Mongolian Autonomous County, Chengde City, Hebei Province. The patient had sudden chest pain on July 30, 2021 at home with continuous tingling in the right chest, radiating to the right shoulder. The pain worsened when respiring deeply, accompanied by chest tightness, shortness of breath, and asthenia. However, there was no fever, cough, sputum, or hemoptysis. She went to the local county-level and then prefecture-level hospitals on July 31 and was suspected of cardiovascular diseases, such as myocardial infarction and aortic dissection. Fever appeared at 14∶30 on August 1. After screening negative for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the fever clinic, the computed tomography (CT) examination at 21∶00 showed lesions in the right pulmonary hilar and mediastinum with suspected space-occupying lesions, bilateral pleural effusion, atelectasis in both lungs, and pericardial effusion. The results of two CT examinations by the hospitals in Beijing were similar.
The patient came to Hospital A in Beijing by an ambulance at 02∶00 on August 3, accompanied by her families. After screening negative for the SARS-CoV-2 in the fever clinic, the patient was given symptomatic anti-inflammatory, analgesic, and antipyretic treatments in the emergency department of Hospital A. Symptoms of pain were relieved. The results of the CT examination showed bilateral pleural effusion, atelectasis in both lungs, and space-occupying lesions in the mediastinum.
At 14∶00 on August 4, the patient was transferred to Hospital B by a Beijing Emergency Medical Center ambulance. The medical record for admission of the patient showed that she had no erythema, papules, or vesicles on the skin of unknown cause and no fever, nausea, or vomiting. Moist rale was found by lung auscultation and the CT showed lesions in the right pulmonary hilar and mediastinum, with suspected space-occupying lesions, bilateral pleural effusion, atelectasis in both lungs, and pericardial effusion. The CT results were similar to previously reported cases (1-2). Other clinical findings were liver injury and hypoalbuminemia. A total of 200 mL of hemorrhagic pleural fluid was collected via the closed thoracic drainage method. The patient was treated with imipenem-cilastatinsodium injection and moxifloxacin hydrochloride sodium chloride injection. The seventh group of lymph nodes was positioned by endobronchial ultrasound (EBUS) and punctured, and some purulent secretions were observed in the puncture fluid. Metagenomic sequencing detected sequences of B. anthracis in the puncture fluid.
Various samples of the patient were collected on August 8, 2021. The sample of pleural effusion was positive for nucleic acid of B. anthracis by fluorescent real-time PCR. Serum antibody against B. anthracis was positive by colloidal gold test (Table 1). As a confirmed case, the patient was transferred to the designated infectious disease hospital for quarantine and treatment on the same day. On August 19 and 20, two samples of pleural effusion within a 24 h-interval collected from the case were negative for B. anthracis by real-time PCR and bacterial culture.
Sample type Colloidal gold test Real-time PCR target genes Bacterial culture Antigen Antibody pagA cap rpoB Oropharyngeal swab Neg Not tested Neg Neg Neg Neg Nasopharyngeal swab Neg Not tested Neg Neg Neg Neg Pleural effusion Neg Not tested Pos Pos Pos Neg Blood Neg Pos Neg Neg Neg Neg Abbreviations: PCR=polymerase chain reaction; Neg=negative; Pos=positive. Table 1. Test results of the patients’ samples on August 8, 2021.
The patient’s home is in the Bashang Grassland, which was a semi-pastoral area, and the patient often had close contact with cattle and sheep. However, the course of the anthrax often progresses rapidly for cattle and sheep and no chronic or carrier states exist. The probability of infection through touching asymptomatic cattle or sheep was estimated to be very low. The patient was also engaged in restaurant operations, so she often visited the meat wholesale market to purchase beef and mutton every two or three days before the disease onset. However, contact with meat or blood of dead animals is more likely to cause cutaneous anthrax instead of inhalational anthrax. The patient had no sign of cutaneous anthrax, no erythema, papule, or verruca, as shown in the medical records of Hospital B, so the probability of infection from exposure to meat from the market was also very low.
The two cattle raised by the patient’s brother-in-law died of an unknown illness in the morning of July 26 and were slaughtered at once in the backyard of the patient’s house. At the same time, the patient’s brother-in-law was told by the doctor that he might have cutaneous anthrax; he called from hospital to stop the slaughtering of the two cattle. The meat, furs, and other parts of the two cattle were disposed outside the village. The slaughter site was immediately disinfected with 1,000 mL of cresol soap solution, the ground was washed with a high-pressure water gun, and the sewage entered the drainage ditch through a drain. In the afternoon, and the next day, the other two cattle died and were buried directly without slaughter. The spore-containing droplets produced by high-pressure water gun washing could be the possible cause of the infection of the patient because she had to pass the slaughter site to go to the toilet.
The patient’s brother-in-law was a 54-year-old male. He felt itchy on the back of his right hand on July 23 and found a rice grain-sized rash that gradually reddened and became swollen with pain. The site of skin turned black after the ulceration without fever. In the morning of July 26, he went to the county hospital. The doctor suspected cutaneous anthrax but results of stained smear examination for the damaged skin was positive for cocci and no bacilli were detected at the time. The doctor still prescribed levofloxacin infusion therapy for him.
The patient’s brother-in-law received levofloxacin infusion therapy for 10 days. He went again to the hospital in town due to pain in his right hand. The hospital found his skin damage site on the back of his right hand to be black with eschar and reported the case. On August 9, the Chengde CDC reported real-time PCR negative results for nucleic acid of B. anthracis of his skin smear sample, but positive for serum antibody against B. anthracis by colloidal gold test. The possible source of infection for the patient’s brother-in-law could be the B. anthracis spores in the soil. The village is located within a historically anthrax-endemic region. The heavy rainfall this year may have caused the spores in the soil to be revealed on the surface and contaminated the grass. The time of infection could be the same as the cattle or when the patient disposed of the sick cattle.
On August 9, 3 samples of furs and 3 samples of beef were collected from the buried dead cattle. The beef samples were positive for nucleic acid of B. anthracis and one strain of B. anthracis was isolated by bacterial culture from one sample of the beef.
Inhalational anthrax is usually caused by inhaled spores of B. anthracis from animal fur, wool, textile mill, or by bioterrorist attack (3). The current case was also related to infected animals because the case was preliminarily attributed to being caused by droplets produced by the high-pressure water gun in the process of washing the grounds where the cattle were slaughtered. In addition, the patient was in poor health and vulnerable to infection. She likely passed the site of slaughtering and became infected.
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