Fever of Unknown Origin in a Migrant Farm Worker from Mexico: History, Her Story and His Story

A 29-year-old migrant farm worker from Mexico presented to a hospital in Ontario with fever of unknown origin. She had arrived in Canada six weeks previously to work at an orchard. Her past medical history included two caesarean sections, postpartum hemorrhage requiring transfusion, and cholecystectomy. She was not on any medications. She began experiencing daily rigors one week after her arrival, often accompanied by drenching sweats, and she lost approximately 5 kg of weight. She had intermittent midthoracic back pain, but no other localizing symptoms. Painful vaginal sores and dysuria developed one week later. She presented to the emergency room, where she was diagnosed with genital herpes simplex and secondary bacterial infection. She was prescribed a one-week course of cephalexin and one dose of azithromycin, but she continued to have rigors. One week later, she developed intermittent epigastric pain with no nausea, vomiting or diarrhea. She returned to the emergency room with a fever of 39.5°C, and was admitted for presumed pelvic inflammatory disease. She was treated with various broad-spectrum antibiotics and acyclovir but remained persistently febrile. All cultures were negative and her pelvic ultrasound was unremarkable. She was transferred to a tertiary care hospital one week later for consultation with an infectious disease specialist. Further questioning revealed that she was from a city in Mexico where she lived in close proximity to chickens. She denied having recent insect bites, sick contacts, intravenous drug use and tattoos. She had two previous male sexual contacts, including her husband, who she said had died at 27 years of age from lung cancer. On examination, she was hemodynamically stable and slightly tachypneic, with a temperature of 38.4°C and an oxygen saturation of 96% on room air. Her head and neck examinations revealed two small umbilicated papules on the right upper eyelid and white lesions on the tongue and buccal mucosa. There was no lymphadenopathy. Her cardiovascular, respiratory, abdominal and neurological examinations were unremarkable. Blood tests on admission were significant for the following: hemoglobin of 90 g/L with a mean corpuscular volume of 75.8 fL, white blood cell count of 3.1×109/L (2.9×109/L neutrophils and 0.2×109/L lymphocytes), aspartate amino-transferase level of 132 U/L, alanine aminotransferase level of 28 U/L, alkaline phosphatase level of 386 U/L, bilirubin level of 6 μmol/L and lactate dehydrogenase level of 1283 U/L. Her chest x-ray showed a diffuse reticulonodular pattern. Diagnostic tests were performed.