A new species of Brucella discovered in 2...

Two cases of brucellosis in men working in separate communes in French Guiana were hospitalized in 2020, the diagnosis of brucellosis was confirmed. Both men were Brazilian nationals working as illegal gold miners in the Amazon rainforest.

• Patient 1, a 39-year-old man from Belem, Brazil, worked as an underground gold prospector. He had lived in Suriname for 10 years and arrived in French Guiana 8 days before his symptoms started in Maripasoula on the Maroni River. He consulted at the Maripasoula health center in early September 2020 for fever, asthenia and back pain. He had no relevant medical history. Clinical examination revealed hepatomegaly. Blood cultures have made it possible to isolate a bacterium of the genus Brucella. The patient denied exposure to farm animals or consumption of unpasteurized milk and cheese, but admitted to consuming game hunted in the forest around the gold mine camp, including wild pig. He was discharged from hospital and returned home, continuing antibacterial therapy for a total of 6 weeks. At the last visit (after 1 month of antibiotics), his evolution was satisfactory, but the patient was not available for further follow-up.
• Patient 2, a 45-year-old man from Macapá, Brazil, who worked as a blacksmith in an illegal gold mine near Apatou. He had lived on both banks of the Maroni River in French Guiana and Suriname since about 2002. In October 2020, the patient consulted at the Saint-Laurent-du-Maroni hospital for fever, low back pain, weight loss and functional discomfort in his left leg. He presented with spondylodiscitis and psoas abscess. A bacterium of the genus Brucella was identified in culture from a sample obtained from the psoas abscess. The patient did not report exposure to farm animals, but did consume meat that was hunted in the forest. His initial clinical course was favorable. Later he was lost sight of.

Bacterial isolates from both patients were sent to the French National Reference Center for Brucella in Nîmes for confirmation of identification. Genome analysis revealed that the 2 bacterial isolates represent a potentially new species of Brucella for which the name Brucella amazoniensis sp. Nov. (Reference: About F, Pastre T, Boutrou M, Yahiaoui Martinez A, Melzani A, Peugny S, et al. Novel Brucella species causing human brucellosis, French Guiana. Emerg Infect Dis. 2023 Feb [date cited]. https://doi.org/10.3201/eid2902.220725).

Reminder about brucellosis

Brucellosis (sometimes also called Maltese fever) is an animal disease that can be transmitted to humans (zoonosis). It is caused by such bacteria Brucella. Three species predominate: Brucella melitensisthe most pathogenic, invasive and widespread species in the world, B. abortion, And b.am. There are other less frequent species, with variable pathogenicity for humans (B. canis, B. ovis, B. marimum, B. inopinataetc.).

Epidemiology

Brucella is found in most mammalian species, including ruminants, both domestic and wild, as well as suidae (pigs and wild boars) and lagomorphs (hares). Those that infect humans come mainly from domestic cattle, sheep, goats and pigs. The fact that wild animals serve as a reservoir of infection complicates eradication efforts.
This bacterial zoonosis is spread all over the world. The annual incidence is 500,000 reported cases.

Humans can be infected in several ways:

• by direct contact (penetration of the germ through the skin or mucous membrane favored by wounds or grazes) with infected animals, animal carcasses, abortion products, placentas, vaginal secretions of animals, manure or by accidental contact with biological products in laboratories; this method of contamination concerns people in direct contact with infected animals (breeders, veterinarians, inseminators, slaughterhouse or sorting personnel) and much more rarely laboratory personnel during veterinary or medical analyses;
• by ingestion of contaminated food (unpasteurized milk and dairy products from contaminated animals, more rarely raw vegetables contaminated by manure or exceptionally undercooked meat and offal); it is the main way of contamination among travelers who share the way of life of the local populations, especially from the food point of view;
• by inhalation (of litter dust, contaminated aerosol in laboratories or slaughterhouses), since the bacteria can survive for several months outside the animal’s body, in the external environment, particularly in cold and humid conditions.

Brucellosis is one of the most serious livestock diseases, given the damage caused by infection in animals. Decreased milk production, weight loss, loss of pups, infertility and lameness are some of the effects on the animals.

Clinical aspects of brucellosis in humans:

The incubation period for brucellosis varies from one week to several months. The primary infection may be asymptomatic, and disease may not become apparent until several months or years later.
In symptomatic forms the clinical signs are quite variable but usually evolve in three phases:

• An acute primary invasion phase: fever associated with myalgia, feeling unwell;
• A secondary phase in which isolated or multiple infectious foci form: osteoarticular (spondylodiscitis, knee arthritis, etc.), genitourinary (orchitis, epididymitis), hepatic (liver abscess), neurological (meningitis, meningoencephalitis, brain abscess…), heart (endocarditis…)
• Possibly, especially in the case of insufficient or poorly followed treatment, a chronic phase whose expression is twofold: either general symptoms (asthenia, pain, fatigue), or more focal symptoms (chronic evolution of infectious foci).

Once the diagnosis is confirmed, the treatment of human brucellosis is based on the administration of specific antibiotics for several weeks and, if necessary, on the surgical management of the infectious foci. Lethality is less than 2% even in the absence of treatment.

The traveler should avoid unpasteurized dairy products and undercooked meat, especially when traveling to countries where brucellosis is endemic.

Source : Emerging infectious diseases.

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