To the editor:
In recent times, we have seen a steep rise in cases of invasive
mucormycosis infection in patients of COVID-19 (Coronavirus infection
disease 2019) in India. We reviewed literature to find plausible cause
of this association. Considering the pathogenesis, fungal spores need to
evade the innate immune system and germinate, leading to angioinvasion
and tissue destruction. Literature states that mucorales are able to
downregulate several host defense mechanisms and attach to the
endothelium via specific receptors, GRP78 facilitating their endocytosis
and angioinvasion. Factors such as hyperglycemia, elevated iron
concentrations, and acidosis have been shown to contribute to the
pathogenesis in experimental setup and animal models. The antifungal
properties of platelets and natural killer cells have been demonstrated
(1). But reasons for mucormycosis happening post covid19 are still not
clear.
Review of literature published till April of 2021 revealed 68 cases of
mucormycosis in patients of COVID-19. Rhino-ocular-cerebral infections
comprised the majority (60/68). Less common sites included pulmonary
mucormycosis (5/68), and 1case each of cutaneous, gastrointestinal tract
and fulminant mucormycosis. India accounted for 75% of published cases
(51/68) (2-10), followed by United States of America (9/68) (11-18),
Iran (4/68) (19-21) and 1 case each from Brazil (22), Mexico (23), Italy
(24) and Austria (25). Most patients suffering this complication of
mucormycosis had some underlying co-morbidity mainly diabetes mellitus,
but infections in immunocompetent persons have also been seen.
The second wave of COVID-19 pandemic in India has seen a sudden surge in
cases of mucormycosis and associated complications of vision loss, brain
abscess and stroke. Both morbidity and mortality are on a rise post this
fungal infection. Maharashtra, a state in India with a population of
approximate 114 million has documented 1500 cases of mucormycosis post
covid-19 with 52 death in last 1-month (26). As per one report, India
has a total of 8,848 mucormycosis cases post covid19 after many states
have made it’s a notifiable disease (27).
Why such a steep rise in cases of mucormycosis post second wave of
covid-19? In second wave India has had too many cases of covid-19 which
hospital system could handle so many patients were prescribed steroids
early and given longer in the hope of avoiding need for oxygen and
hospital admission. India is the diabetes capital of India. Severe
Covid-19 causes activation of immune system which raises ferritin.
Covid-19 is frequently associated with lymphopenia. So, a combination of
steroids, diabetes, high ferritin and lymphopenia might be contributing
to this sudden and steep rise (1,3). Another factor could be that new
strain of SARS-COV-2, B.1.617 reported in this second wave in India is
more infectious so more cases and also it is somehow promoting entry of
mucorales into the patients. With such rapid rise in cases there is an
urgent need to identify patients at risk of this infection and start
urgent treatment to save lives and avoid debilitating complications.
Mucormycosis post covid19 in India has reached epidemic proportions and
more research is needed about this association.