**2. Factors that may encourage rare diseases**

#### **2.1 Technology and occupation**

As knowledge multiplies, it acts synergistically with technology, and recent advances in the field of environmental health are a gateway to health hazards, risks, and susceptibilities. Technological advances have brought more people together, increased production processes but inadvertently led to more consumption, and accompanied wastes (gaseous emission, solid, and liquid waste), which exacerbate human health *via* devastation of aquatic ecosystem, pressure on water resources, deforestation, and increase in agricultural chemicals. Human occupational exposure/ contact through inhalation, ingestion, and dermal contact causes enzyme hormonal

distortion, inhibits fetal growth, and activates DNA damage. A hallmark of technology is in industrial emission, transportation such as roads, aviation, radiation from telecommunication, and military armaments activates climate change imprint. Air pollution occasioned by dust particles, vehicular emission, soot, nitrates, NH3 and nitrogenous gaseous oxides (NOx), oxides of sulfur, aerosols, CH3, PM2.5, and PM10 activate biomarkers (ceruloplasmin, orosomucoid, C3, and alpha-1-antitrypsin), which may be a pointer to high risk at moderate exposure levels that significantly and positively elevate the risk of cardiovascular disease *via* chronic systemic inflammation [4]. The aforementioned effect also exacerbates and promotes progression of atherosclerosis and ups cardiovascular events, including regularity of noncommunicable respiratory diseases (NCRDs) with asthma, chronic bronchitis, obstructive respiratory disease, and allergic rhinitis [5, 6]. Human ailments such as cancer, renal issues, cognitive impairment, bronchitis, and neurological disorders have been attributed to environmental toxicants such as heavy metals (Cd, Ni, Cr, Pb, Hg, As) [7], which partly correlates with findings of Unachukwu et al. [1], agreeing with several pieces of literature linking heavy metals to noncommunicable diseases. Pb+2 and metals like Cd+2 activates blood lipids, which undermine cardiovascular ailment (CVD) and atherosclerosis, exacerbating blood pressure (BP) rise and hypertension that triggers stroke, diabetes, pollution keratoconjunctivitis (PKC) [8–10]. Human factors that may exacerbate the occurrence of rare diseases may include low attention emission from pharmaceutical industries, inappropriate government policy, lack of public health advocacy groups, poor coverage, low monitoring, and inadequate reportage by the global health research community. Occupational **e**xposure plays a major role in rare disease occurrence**,** hexavalent chromium (Cr+6) is carcinogenic, corrodes skin, and causes denaturation and precipitation of tissue proteins [11]. Occupational exposure to chromium is mostly by inhalation, but gastrointestinal tract and skin can occur [12], hence respiratory tract is the primary target organ for Cr+6 and its compounds. Nickel is absorbed through the lungs [13, 14], gastrointestinal tract [15], and skin [16], but excreted in the urine [17]. Artisanal effect, respiratory abnormalities, and industrial occupation take a huge aspect of rare disease that may be undocumented [18] and show that it may be significant in public health issues through occupational exposure considering the work of Orisakwe et al. [19, 20] and that of Vitayavirasuk et al. [21], which shows that subjects exposed to heavy metal in a paint factory and automobile paint spray may have compromised health status.
