with open(input_file) as f_in:
    np.genfromtxt(itertools.islice(f_in, 2, None, 4), dtype=None, delimiter=','
        )
f_in.seek(0)
low = np.genfromtxt(itertools.islice(f_in, 3, None, 4), dtype=str)
f_in.seek(0)
up = np.genfromtxt(itertools.islice(f_in, 4, None, 4), dtype=str)
Using multiple genfromtxt on a single file