The Ministry of Agriculture, Livestock and Supply (Map) released a note in which it warns about a possible relationship between the cases of Half’s disease, known as “black urine”, observed this year in Brazil, and the consumption of fish, shellfish and crustaceans without the seal of the official inspection bodies.
According to the folder, all notified cases and under investigation are being monitored by epidemiologists from the Ministry of Health, in cooperation with the Federal Agricultural Defense Laboratories (LFDA) and the Federal Institute of Santa Catarina (IFSC).
Haff’s disease presents as symptoms muscle stiffness often associated with the appearance of dark urine, which results from renal failure. It constitutes a type of rhabdomyolysis, a name given to designate a syndrome that generates the destruction of skeletal muscle fibers and releases elements from within the fibers – such as electrolytes, myoglobins and proteins – into the blood.
The note on the map informs that the first signs and symptoms can appear within 24 hours of consuming boiled fish, crayfish and other contaminated seafood. “The disease is considered to be emerging and, as it has an unknown origin, it is classified as a public health event (ESP), being considered a mandatory notification”, says the note.
Also according to the ministry, the first cases of Half’s disease registered in Brazil were in 2008, originating from freshwater species such as Pacu (Mylossoma spp), tambaqui (Colossoma macropomum) and pirapitinga (Piaractus brachypomus), as well as fish of salt water, such as arabaiana/bullet’s eye (Seriola spp) and whiting (Mycteroperca spp).
Cases were also registered in 2016 and now in 2021. In view of the situation, the Map is instructing the population to pay attention when buying fish, in general. “Fish, shellfish and crustaceans sold must bear the seal of the official inspection bodies”, warns the ministry, informing that products identified by the inspection stamp on the labeling enable traceability of their origin, which makes them safe.
The difficulty in identifying the contaminated material lies in the fact that the causing toxin does not have a specific taste or smell, which makes its perception more complex. In the reports recorded over the years, people affected by the disease ate different types of fish, such as salmon, pacu-butter, pirapitinga, tambaqui, and from several families such as Cambaridae and Parastacidae.
“Researches on possible causative agents are being carried out by the LFDA and the IFSC, based on samples collected from the food consumed, as well as biological material from the affected patients themselves. As it has been recorded in several biomes (rivers, lakes, seas, etc.) and species, it is not possible, so far, to determine, based on the cases analyzed, the environments and animals involved”, informs the note.
According to the map, sample surveys were carried out in search of “suspicious molecules”, especially from groups where toxins causing Haff disease are more likely to be found. In this case, “analogous molecules that can be produced by toxic microalgae”.