A Brief and Critical Review of Chronic Fluoride Poisoning (Fluorosis) in Domesticated Water Buffaloes (Bubalus bubalis) in India: Focus on its Impact on Rural Economy

Abstract

In the rural areas of India, fluoridated drinking water, industrial fluoride pollution and fluoride-rich feed phosphate supplements are the major sources of fluoride exposure for domesticated water buffaloes (Bubalus bubalis). However, the fluoridated drinking groundwater is the commonest and principal source of fluoride exposure for these ruminants. Chronic fluoride exposure for long-time deteriorate the animal health and causes the fluorosis disease. In the country, the drinking groundwater sources of villages are contaminated with fluoride beyond the threshold value, 1.0 or 1.5 mg/L. At 1.5-1.7 ppm fluoride concentration in drinking water, 62.2% and 21.6% calves and 55.9% and 48.3% adult buffaloes are found to be afflicted with dental and skeletal fluorosis, respectively. The maximum prevalence of dental and skeletal fluorosis, 96.8% and 34.4% in calves and 66.9% and 60.2% in adult buffaloes has also been reported at or > 3.0 ppm fluoride in drinking water, respectively. However, calves are found to be more sensitive and susceptible to chronic fluoride toxicity or fluorosis. Besides the deterioration of the animal health, chronic fluoride intoxication in buffaloes also weakens the rural economy which has been focussed in the present review. In this communication, besides the status of chronic fluoride intoxication in the form of osteo-dental and non-skeletal fluorosis in buffaloes, determinations, bio-indicators and bio-markers of fluorosis and prevention and control of chronic fluoride poisoning in these animals are also considered and briefly and critically reviewed. Simultaneously, research gaps are also identified and highlighted them for further research study on chronic fluoride intoxication in buffaloes. Findings of this review may help in preparation of health policy for improving the health and mitigation of fluorosis in economically important buffalo animals in the country.

The Diagnosis and Prevention of Fluorosis in Humans

“…Dental fl uorosis may also be seen in the form of white or light to deep brownish spots, patches and fi ne dots or granules on the enamel of teeth. In its severe form, pronounced loss of the tooth-supporting alveolar bone occurs with recession and swelling of the gingival tissues and excessive abrasion or irregular wearing of the teeth [20].…”

“…The diverse fl uoride induced toxic eff ects in soft organs are gastrointestinal discomforts (intermittent diarrhoea or constipation, abdominal pain, flatulence etc. ), urticaria, frequent tendency to urinate (polyurea), excessive thirst (polydipsia), neurological disorders, impaired endocrine and reproductive functions, teratogenic eff ects, renal eff ects, genotoxic eff ects, apoptosis, excitotoxicity, asthma, genital pruritus, lethargy, muscle weakness, bronchitis with violent cough, nasal irritation, irregular reproductive cycles, abortion and still birth [20]. These are the earlier signs of chronic fl uoride toxicosis in people of fl uoride endemic areas.…”

“…However, among these bio-samples, urine is the most ideal biomarker for the assessment of fl uoride toxicosis because at the spot, it can be easily recollected noninvasively and systematically [27]. In fact, the level of fl uoride in the urine gives the best indication of the presence of chronic fl uoride poisoning and revealed its current status [20]. In the normal or healthy subjects, the normal range of fl uoride ion in serum and urine is reported as 0.02-0.15 mg/L and 0.1-1.0 mg/L, respectively [28][29][30].…”

How Can Fluorosis in Animals be Diagnosed and Prevented?

“…Once dental fluorosis and skeletal fluorosis develop in animals, then these are not cured by any treatment. These dental and bone deformities not only cause a lot of trouble to the animals, but they also cause economic loss to the livestock owners [29]. But the occurrence of fluorosis disease in animals can be prevented.…”

“…In some animals, F is considered to be an essential element, as diets low in F impaired fertility and development [5]. When F is ingested in a small quantities then it becomes beneficial for dental health by reducing the dental caries, whereas higher concentrations, >1.0 or 1.5 mg/L or ppm [1] may cause fluorosis in both humans [6][7][8][9][10][11][12] and diverse species of domestic and wild mammalian animals [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Once F enters the body it is absorbed by the digestive and/or respiratory systems.…”